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LAB
MANUAL
Course: CSC103-Programming Fundamentals
Department of Computer Science
Learning Procedure
J (Journey inside-out the concept)
Stage a1 (Apply the learned)
Stage v (Verify the accuracy)
Stage a2 (Assess your work)
1) Stage
2)
3)
4)
COMSATS University
Islamabad (CUI)
undamentals
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Table of Contents
Lab #
Lab # 01
Topics Covered
Lab # 04
Introduction to Flowcharting using Raptor
Basic Flowcharting symbols and their use
Selection and Iteration Symbols in Raptor and their usage
Java Installation
FirstProgram in Java
if-else structure, nested if statements
Lab # 05
for loop, nested for loops
Lab # 02
Lab # 03
Page #
Lab Sessional 1
Lab # 06
while and do-while loops
Lab # 07
Methods
Lab # 08
Arrays (1-D & 2-D)
Passing arraysto methods
Strings
Lab # 09
Lab # 10
Methods Overloading
Recursion
Lab Sessional 2
Lab # 11
File handling I
Lab # 12
File handling II
Lab # 13
Test cases
Lab # 14
Test cases generations
Terminal Examination
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LAB # 01
Statement Purpose:
The objective of this lab is to make student familiar with basic programming concepts
using flowcharting techniques.
Activity Outcomes:
This lab teaches you the following topics:



An introduction to Raptor Tool
Basic flowchart Symbols
Creating, Running and Saving flowcharts in Raptor
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1)
StageJ(Journey)
Introduction:
Make yourself familiar with the Raptor Tool
1.1
Understand the symbols for Input, Process and Output
1.2
Placing symbols and saving your first flowchart
1.3
Running the flowchart and getting the output in console
Making program flowcharts is a powerful technique for logic building and
learning syntax free programming. Using Raptor, a GUI based drag and
drop tool you can easily test your logic building skill, just drape your logic
with the syntax of any programming language and claim yourself to be a
programmer.
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2) Stage a1 (apply)
Lab Activities:
Activity 1:
Create flowchart for “Hello World”
Solution:
Launch Raptor, you will see two set of windows, the main working pane and
the console window.
The main window is where you can drag and drop symbols and test your logic
while the console window gives you output and some basic information
regarding the last execution done.
The start and end symbols are placed by default.
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Task 1.1: Hello World and it's Execution
➜ Pick the output symbol from symbols pane and drag it in between the start
and end symbol, the application might ask you to save your work, give it a
meaningful name like HelloWorld and it
will be saved with rap extension.
➜ Single click inside the output symbol to
select it.
➜ Double click inside the output symbol
and you will see a popup window asking
what you want to output.
➜ In the output popup window type (with
double quotes) “Hello World”.
➜ You can optionally change the speed of
execution using the scrolling pointer
given immediately after the buttons
toolbar.
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Activity 2:
Flowchart for calculating Area of Circle
Solution:
The formula to calculate area of circle is
Area = 3.1415 * radius * radius
It's clear that the only variable in the above formula is “radius” of the circle, this means
we require it as an input from user to get a meaningful answer of the expression.
➜ Select the New option from File menu
●
Place the Input Symbol from the list of symbols.
●
Place the Assignment Symbol just below the Input Symbol.
Finally place an Output Symbol after the Assignment and just
before the End Symbol.
●
➜ Double click on the input symbol and tell the
Raptor the message you want to display in the
Prompt section and the variable name in which
you want to store the input from the user.
➜ Double click the Assignment Symbol and
introduce a new variable named “area” in the Set
field and the formula for expression in the “to”
field.
➜ Double click the Output Symbol and tell the
Raptor what you want to display as output, the
literal message in double quotes concatenated with
the plus symbol and the variable whose value you
want to display.
"The Area of Circle with Radius " + radius + " is
" + area
➜ Execute the flow chart, give the required input for “radius” and verify the output.
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Activity 3:
Update Activity 2 to calculate Perimeter of Circle (2*3.1415*radius) along with Area
3) Stage v (verify)
Home Activities:
1. Create a flowchart that prompts the user to enter two points (x1, y1) and (x2, y2) and
displays their distance between them. The formula for computing the distance is
sqrt((x2 - x1)2 + (y2 - y1)2). Note that you can use the built-in method sqrt(x) for
calculating square root of a given number.
2. Given an airplane’s acceleration a and take-off speed v, you can compute the minimum
runway length needed for an airplane to take off using the following formula:
length = (v * v)/(2*a)
Draw a flowchart that prompts the user to enter v in meters/second and the acceleration a in
meters/second squared and displays the minimum runway length.
4)
Stagea2(assess)
Lab Assignment and Viva voce
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LAB # 02
Statement Purpose:
The objective of this lab is to make student understand the basic concepts of selection
and looping using flowcharting technique in Raptor.
Activity Outcomes:
This lab teaches you the following topics:


At the end of this lab student will know how to develop logic of a program
Students will get clear understanding of two important Problem-Solving techniques which
are:
o Selection
o Iteration or Looping
Instructor Note:
As pre-lab activity, the concepts from Chapter 3 and Chapter 5 are covered from the
book (Introduction to JAVA Programming, Liang, Y.D., 10th Edition (2015), Prentice
Hall).
Although it’s too early to go in to the details of selection and looping in second lab but a
quick overview and concept of both can be introduced so that students can practice the
two important options given in the Raptor’s symbol list.
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1) StageJ(Journey)
Introduction
Selection
Selection means selecting a set of statements for execution under a certain condition, the condition
should a logical test involving logical and relational operators, e.g. display A/B only when B is not
equal to zero, means we have to test B for the specific value of zero.
Raptor uses the symbol
for selection type
statements .
the diamond symbol
represents the logical test and YES branch
means execution path when condition evaluates to be true, obviously NO side branch represents
execution path when the condition evaluates to be false.
Iteration or Looping
Iteration means repetition i.e. to repeat a set of statements a certain number of times or to repeat
the statements until a specific condition is met, e.g. if the user enters a negative value for his age
then ask him to enter the age repeatedly until he enters a value greater than zero.
Raptor uses the symbol
for looping.
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2)
Stage a1 (apply)
Lab Activities:
Activity 1:
Draw a flowchart that tells user whether the Integer entered is Even or Odd Number,
use % symbol to test the remainder value.
Solution:
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Activity 2:
Draw a flowchart to accept two values from user and display the larger one.
Solution:
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Activity 3:
Draw a flowchart for a program that reads two numbers and displays the number series
from first to last number.
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3) Stagev(verify)
Home Activities:
1. Draw a flow chart to calculate the Sum of series from Starting to Ending Number, the
increment per cycle is also entered by the user.
2. Construct flow chart to Calculate Factorial of a Number entered by the user.
4)
Stagea2(assess)
Lab Assignment and Viva voce
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LAB # 03
Statement Purpose:
This lab covers the following topics:
•
•
•
•
•
•
•
Install NetBeans
Getting Started with NetBeans
Creating a Project
Creating a Class
Compiling a Class
Running a Java Application
Forcing a Program to Terminate
This tutorial applies to NetBeans 6, 7, or a higher version.
Activity Outcomes:
This lab teaches you the following topics:


Installing java
Create first java program
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1)
StageJ(Journey)
Introduction
This tutorial is for students who are currently taking a Java course using
NetBeans with Introduction to Java Programming.
You can use the JDK command line utility to write Java programs. The JDK
command line utility consists of a set of separate programs, such as compiler and
interpreter, each of which is invoked from a command line. Besides the JDK command
line utility, there are more than a dozen Java development tools on the market today,
including NetBeans, JBuilder, and Eclipse. These tools support an integrated
development environment (IDE) for rapidly developing Java programs. Editing,
compiling, building, debugging, and online help are integrated in one graphical user
interface. Using these tools effectively will greatly increase your programming
productivity.
This brief tutorial will help you to become familiar with NetBeans. Specifically,
you will learn how to create projects, create programs, compile, run, and debug
programs.
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2)
Stage a1 (apply)
Lab Activities:
Activity 1:Install NetBeans
Download and install JDK 1.8 and NetBeans 8.0 from one bundle
at
http://www.oracle.com/technetwork/java/javase/downloads/jdknetbeans-jsp-142931.html
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Activity 2:Getting Started with NetBeans
Assume that you have successfully installed NetBeans on your machine. Start NetBeans from
Windows, Linux, Mac OS X, or Solaris. The NetBeans main window appears, as shown in Figure 1.
Figure 1
The NetBeans main window is the command center for the IDE.
The NetBeans main window contains menus, toolbars, project pane, files pane, runtime pane,
navigator pane, and other panes.
1.1 The Main Menu
The main menu is similar to that of other Windows applications and provides most of the
commands you need to use NetBeans, including those for creating, editing, compiling, running, and
debugging programs. The menu items are enabled and disabled in response to the current context.
1.2 The Toolbar
The toolbar provides buttons for several frequently used commands on the menu bar. The toolbars
are enabled and disabled in response to the current context. Clicking a toolbar is faster than using
the menu bar. For many commands, you also can use function keys or keyboard shortcuts. For
example, you can save a file in three ways:
•
Select File, Save from the menu bar.
•
Click the "save" toolbar button ( ).
•
Use the keyboard shortcut Ctrl+S.
TIP: You can display a label known as ToolTip for a toolbar button by pointing
the mouse to the button without clicking.
1.3 Workspaces
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A workspace is a collection of windows that are pertinent to performing certain types of
operations, such as editing, execution, output, or debugging. The workspace windows can be
displayed from the Window menu.
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Activity 3:Creating a Project
A project contains information about programs and their dependent files, and it also stores and
maintains the properties of the IDE. To create and run a program, you have to first create a project.
Here are the steps to create a demo project:
1. Choose File, New Project to display the New Project dialog box, as shown in Figure
2.
2. Select General in the Categories section and Java Application in the Projects section and
click Next to display the New Java Application dialog box, as shown in Figure 3.
3. Type demo in the Project Name field and c:\michael in Project Location field.
4. (Optional) You can create classes after a project is created. Optionally you may also create
the first class when creating a new project. To do so, check the Create Main Class
box and type a class name, say First, as the Main Class name.
5. Click Finish to create the project. The new project is displayed, as shown in Figure 4.
Figure 2
The New Project dialog box enables you to specify a project type.
Figure 3
The New Java Application prompts you to enter a project name,
location, and a main class name.
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Figure 4
A new demo project is created.
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Activity 4:Creating a Class
You can create any number of classes in a project. Here are the steps to create Welcome.java.
1. Right-click the top demo node in the project pane to display a context menu, as shown in
Figure 5. Choose New, Java Class to display the New Java Class dialog box, as shown
in Figure 6.
2. Type Welcome in the Class Name field and select the Source Packages in the Location
field. Leave the Package field blank. This will create a class in the default package. (Note
that it is not recommended to use the default package, but it is fine to use the default
package to match the code in the book. Using default package is appropriate for new Java
students. Section 10, “Using Packages,” will introduce how to create a class in a nondefault package.)
3. Click Finish to create the Welcome class, as shown in Figure 7. The source code file
Welcome.java is placed under the <default package> node, because you did not specify a
package name for the class in Figure 6.
4. Modify the code in the Welcome class to match Listing 1.1, as shown in Figure 8.
Figure 5
You can create a new class in a project.
Figure 6
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The New Java Class dialog box enables you to specify a class name,
location, and package name to create a new class.
Figure 7
A new Java class is created in the project.
Figure 8
The source code for Welcome.java is entered.
TIP
You can show line numbers in the Source Editor by choosing View, Show Line
Numbers from the main menu.
NOTE
The source file Welcome.java is stored in c:\michael\demo\src.
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Activity 5:Compiling a Class
To compile Welcome.java, right-click Welcome.java to display a context menu and choose
Compile File, or simply press F9, as shown in Figure 9.
The compilation status is displayed in the Output pane, as shown in Figure 10. If there are no
syntax errors, the compiler generates a file named Welcome.class, which is stored in
c:\michael\demo\build\classes.
Figure 9
The Compile File command in the context menu compiles a source file.
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Output pane
Figure 10
The compilation status is shown in the output pane.
NOTE: When you compile the file, it will be automatically saved.
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Activity 6:Running a Java Application
To run Welcome.java, right-click Welcome.java to display a context menu and choose Run
File, or simply press Shift + F6, as shown in Figure 12. The output is displayed in the Output pane,
as shown in Figure 13.
Figure 12
The Run File command in the context menu runs a Java program.
Output
Figure 13
The execution result is shown in the Output pane.
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NOTE: The Run File command invokes the Compile File command if the program
is not compiled or was modified after the last compilation.
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Activity 7:Forcing a Program to Terminate
If a program does not terminate due to a logic error, you can force it to terminate by clicking the
Stop icon, as shown in Figure 18.
Figure 18
You can force a program to terminate from the runtime pane.
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3) Stagev(verify)
Home Activities:
1. Every student is required to make installation on his / her personal computer before
next lab.
4)
Stagea2(assess)
Lab Assignment and Viva voce
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LAB # 04
Statement Purpose:
This lab will give you practical implementation of different types of Conditional Statements (ifelse and switch).
Activity Outcomes:
This lab teaches you the following topics:





Use of indentation
Use of simple if statement
Use of if-else statement
Use of nested-if statement
Use of switch statement
Instructor Note:
As pre-lab activity, read Chapter 3 from the book (Introduction to Java Programming, Brief VersionPrentice Hall (2012) By Y. Daniel Liang), and also as given by your theory instructor.
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1) Stage J (Journey)
Introduction:
if statement is used to perform logical operation. In order to perform decision making, we need
to check certain condition(s) before processing. Java supports if statement for doing so. There
are various formats of if statement including if-else and if-ellse-if.
Apart from if statement, Java also supports switch statement. switch statement is used to select
one of the various options.
The basic and shortest form of if statement is as below:
if (condition)
statement;
If the condition is true in above case then the statement written after the if statement will be
executed otherwise the given statement will be simple ignored. If there are more than one
statements to be executed when the condition is true then we need to write those statements in
a pair of curly brackets as below.
if (condition)
{
statement1;
statement2;
…
…
}
If the condition is true then the specified block of statements written within a pair of curly
brackets will be executed. It is important to note that the block is specified by the use of a pair of
curly brackets.
We can also write the else block associated with the if statement as below.
if (condition)
statement1;
else
statement2;
The else part of if statement is always optional but if is written then will be executed only if the
condition written after the if statement is false. In above case if the condition is true then
statement1 will be executed and statement2 will be ignored. On the other hand, if the
condition written after the if statement is false then statement2 will be executed and
statement1 will be ignored.
We can also write more than one statements in the if block or in the else block as shown below.
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if (condition)
{
statement1;
statement2;
…
…
}
else
{
statement3;
statement4;
…
…
}
If we are required to test a number of conditions and want to execute one of the many blocks of
statements, then we can use multi-way if-else statements as below.
if (condition1)
{
statement1;
statement2;
…
…
}
else if (condition2)
{
statement3;
statement4;
…
…
}
else if (condition3)
{
statement5;
statement6;
…
…
}
else
{
statement7;
statement8;
}
In the above case only one of the written blocks will be executed depending on the condition to
be true. If none of the conditions is true then the block written after the last else will be
executed. If we have not written the last block then nothing will be executed if all the conditions
are false.
Java supports another statement as alternative of the above case, called switch statement as
discussed below.
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switch statement
The syntax of switch statement is as below.
switch (variable/expression)
{
case value1:
statement1;
statement2;
…
…
break;
case value2:
statement3;
statement4;
…
…
break;
case value3:
statement5;
statement6;
…
…
break;
default:
statement7;
statement8;
…
…
break;
}
In switch statement, only one of the case block can be executed depending on the value of the
variable or expression written after the switch statement. Every case block will have a unique
value and will be executed if the value hold by the switch variable (or expression) matches that
case value. The break statement is important to write in each case block. It takes control out of
the switch statement. If break statement is not written in any case block then the following
case block will be executed until break statement is found or the last statement written in the
switch statement is executed. The default block is optional and will be only executed if none of
the case value is equal to the value contained of the switch variable (or expression).
2) Stage a1 (apply)
Lab Activities:
Activity 1:
Let us take an integer from user as input and check whether the given value is even or
not.
Solution:
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A. Create a new Java file using an appropriate IDE and type the following code.
B. Run the code.
You will get the following output.
Activity 2:
Let us modify the code to take an integer from user as input and check whether the
given value is even or odd. If the given value is not even then it means that it will be odd.
So here we need to use if-else statement an demonstrated below.
Solution:
A. Create a new Java file using an appropriate IDE and type the following code.
B. Run the code by pressing F5.
You will get the following output.
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Activity 3:
Let us modify the above code in order to apply nested if structure. Sometimes we need
to use an if statement within the block of another if to find the solution of the problem.
The following code example illustrates that how nested if can be used in Java.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
You will get the following output.
Activity 4:
The code written in activity 3 can also be written as multi-way if-else statement and is
in fact a preferred way of writing multiple if-else statements in order to make the code
more readable.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
Activity 5:
In this activity, you will be using multi-level if-else statement. You are required to accept
two integer values from user and calculate their addition, subtraction, multiplication
and division depending on the given choice.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
Activity 6:
In this activity, you will rewrite the above code by using switch statement instead of
using multi-level if-else statement. You are required to accept two integer values from
user and calculate their addition, subtraction, multiplication and division depending on
the given choice.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
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3) Stage v (verify)
Home Activities:
Activity 1:
Write a Java code to accept marks of a student from 1-100 and display the grade
according to the following formula.
Grade F if marks are less than 50
Grade E if marks are between 50 to 60
Grade D if marks are between 61 to 70
Grade C if marks are between 71 to 80
Grade B if marks are between 81 to 90
Grade A if marks are between 91 to 100
Activity 2:
Write a Java code to accept temperature value from user (in centigrade) and display an
appropriate message as below.
FREEZING if temperature in less than 0
COLD if temperature is between 0 to 15
WARM if temperature is between 16 to 30
HOT if temperature is between 31 to 40
VERY HOT if temperature is greater than 40
4) Stage a2 (assess)
Assignment:
For this student will submit Lab Assignment before the deadline.
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LAB # 05
Statement Purpose:
This lab will give you practical implementation of different types of for loops including
nested for loops.
Activity Outcomes:
This lab teaches you the following topics:



for loop
nested for loop
Use of break statement in for loop
Instructor Note:
As pre-lab activity, read Chapter 4 from the book (Introduction to Java Programming, Brief VersionPrentice Hall (2012) By Y. Daniel Liang), and also as given by your theory instructor.
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1) Stage J (Journey)
Introduction:
Loops are one of the basic structures of a programming language. Loops are performed
to repeat a step or steps for a certain number of times. Java offers a number of loop
statements. One of them is for loop. This lab session covers the for loop.
for loop
for loop is probably the most commonly used loop in Java. It is preferred to use in
situations when the number of iterations are known in advance, i.e. we already know
that how many times the loop will be repeated.
The syntax of for loop is as below.
for(exp1;exp2;exp3)
statement;
or
for(exp1;exp2;exp3)
{
statement1;
statement2;
statement3;
…
…
}
Where,
exp1 is called initialization. Here we initialize the variable to be used to control the
loop iterations.
exp2 is a condition. Loop will continue to iterate as long as this condition is true.
exp3 is an increment or decrement statement. It will increment or decrement the loop
variable initialized in exp1.
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2) Stage a1 (apply)
Lab Activities:
Activity 1:
Calculate the sum of all the values between 0-10 using for loop.
Solution:
C. Create a new Java and type the following code.
D. Run the code by pressing F5.
You will get the following output.
Activity 2:
Accept an integer values from user and display its numeric table.
Solution:
C. Create a new Java file and type the following code.
D. Run the code by pressing F5.
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You will get the following output.
Activity 3:
Accept an integer values from user and display its factorial.
Solution:
C. Create a new Java file type the following code.
D. Run the code by pressing F5.
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You will get the following output.
Activity 4:
Write a Java code to accept an integer value from user and check that whether it is
prime or not. In this activity, you will also learn the use of break statement in for loop.
break statement is used in for loop to terminate the for loop immediately and the next
iterations will not be performed as they may not be required further.
Solution:
C. Create a new Java file and type the following code.
D. Run the code by pressing F5.
You will get the following output.
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Activity 5:
In this activity, you will learn the use of nested for statements. If we use a for statement
within the body of another for statement then it is called nested for statements. You
are required to write a Java program to display all the prime numbers between 100 to
200.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
You will get the following output.
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3) Stage v (verify)
Home Activities:
Activity 1:
Write a Java program to accept 10 integer values from user and display sum of positive
values.
Activity 2:
Write a Java program to generate the following output.
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Activity 3:
Write a Java program that prompts the user to enter two positive integers and find their
greatest common divisor as below.
Activity 4:
Fibonacci series is that when you add the previous two numbers the next number is
formed. You have to start from 0 and 1.
E.g. 0+1=1 → 1+1=2 → 1+2=3 → 2+3=5 → 3+5=8 → 5+8=13
So the series becomes
0 1 1 2 3 5 8 13 21 34 55 ……………………………………
Steps: You have to take an input number that shows how many terms to be displayed.
Then use loops for displaying the Fibonacci series up to that term e.g. input no is =6 the
output should be
011235
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4) Stage a2 (assess)
Assignment:
For this student will submit Lab Assignment before the deadline.
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LAB # 06
Statement Purpose:
This lab will give you practical implementation of while and do-while loops.
Activity Outcomes:
This lab teaches you the following topics:


while loop
do-while loop
Instructor Note:
As pre-lab activity, read Chapter 4 from the book (Introduction to Java Programming, Brief VersionPrentice Hall (2012) By Y. Daniel Liang), and also as given by your theory instructor.
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1) Stage J (Journey)
Introduction:
Java provides different types of loop statements including while and do-while
statements. Although these loop statements can be used as alternatives of for loop but
are preferred to be used when the number of iterations are not known in advance.
while loop
This is also called as pre-test loop where a condition is tested first before the body of the
loop is executed. The body of the loop is executed as long as the condition followed by
the while statement remains true. The syntax of while loop is as below.
while (condition)
{
statement1;
statement2;
...
...
}
As you can see in the above syntax, a condition is followed by the while statement. This
condition must remain true for the execution of the loop. As long as the condition will
remain true, the loop will be iterated and will stop when the condition becomes false.
do-while loop
This is also called post-test loop where the condition is tested once the body of the loop
is executed. If the condition is true then the body of the loop is executed again and this
process continues until the condition becomes false. It means that the body of the loop
will be executed at least once whether the condition is true or false as the body is
executed first and then the condition is checked. The syntax of do-while loop is as
below.
do
{
statement1;
statement2;
...
...
}while (condition);
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2) Stage a1 (apply)
Lab Activities:
Activity 1:
Calculate the sum of all the values between 0-10 using while loop,
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
You will get the following output.
Activity 2:
Repeat the above code by accepting 5 integer values from user and display the sum of
given values.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
Activity 3:
Rewrite the above code to keep accepting integer values from user until 0 is entered.
Display sum of the given values.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
Activity 4:
Rewrite the above code using do-while loop.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
You will get the following output.
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Activity 5:
Write a Java program to accept two integer values from user and calculate their
addition, subtraction, multiplication and division depending on the given choice. Keep
accepting the values until a choice related to quit the process is selected.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
You will get the following output.
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3) Stage v (verify)
Home Activities:
Activity 1:
Write a Java program that prompts the user to enter an answer for a question on
addition of two single digits and let the user repeatedly enter a new answer until it is
correct as below.
Activity 2:
Guessing Numbers---The problem is to guess what number a computer has in mind. You
will write a program thatrandomly generates an integer between 0 and 100, inclusive.
The program prompts the user to enter a number continuously until the number
matches the randomly generated number. For each user input, the program tells the
user whether the input is too low or too high, so the user can make the next guess
intelligently. Here is a sample run:
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Activity 3:
Write a Java program to keep accepting integer values from user until a prime number
is entered.
Activity 4:
Write a Java program to keep accepting marks and names of students until a negative
number is entered against marks. Display name of the student having maximum marks.
4) Stage a2 (assess)
Assignment:
For this student will submit Lab Assignment before the deadline.
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LAB # 07
Statement Purpose:
This lab will give you practical implementation of different types of user-defined methods.
Activity Outcomes:
This lab teaches you the following topics:



How to define own methods
How to use user-defined methods
Passing different types of arguments
Instructor Note:
As pre-lab activity, read Chapter 5 from the book (Introduction to Java Programming, Brief VersionPrentice Hall (2012) By Y. Daniel Liang), and also as given by your theory instructor.
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1) Stage J (Journey)
Introduction:
It is usually a better approach to divide a large code in small methods. A method is a
small piece of code used to perform a specific purpose. Methods are defined first then
called whenever needed. A program may have as many methods as required. Similarly a
method may be called as many times as required.
How to Define Methods
Functions are defined as below.
returnType methodName(dataType par1, dataType par2, ...)
{
statement1;
statement2;
...
return value;
}
A method may or may not return a value. If a method does not return a value then the
return type must be void otherwise you need to return the data type of the value to be
returned.
A method must have an appropriate name and a pair of parenthesis. In parenthesis, you
need to mention that whether a method will accept or not any parameters. If a method
is not accepting any parameter then the parenthesis must be left blank otherwise you
need to mention the name and type of parameters to be accepted.
A method must return a value if the return type is not void.
How to Call A Function
Once a method is defined then it can be called by using its name and providing values to
the parameters. The following activities demonstrate that how methods are defined and
called in Java.
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2) Stage a1 (apply)
Lab Activities:
Activity 1:
Define a method to accept an integer value and return its factorial.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
You will get the following output.
Activity 2:
Write a function to accept 2 integer values from user and return their sum.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
Activity 3:
Define a function to accept an integer value from user and check that whether the given
value is prime number or not. If the given value is a prime number then it will return
true otherwise false.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
Activity 4:
Define a function to accept an integer value and display its numeric table.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
Activity 5:
Write a Java program to find the sum of integers from 1 to 10, from 11 to 20, and from
21 to 30, respectively.
Solution:
A. Create a new Java file and type the following code.
B. Run the code by pressing F5.
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You will get the following output.
3) Stage v (verify)
Home Activities:
Activity 1:
Write a method to accept an integer ‘n’ and display ‘n’ elements of Fibonacci series.
Activity 2:
Write a method to accept three integer values and return the largest value.
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Activity 3:
Write a method to accept marks of a student (between 0-100) and return the grade
according to the following criteria.
0 - 49
50 – 60
61 – 70
71 – 80
81 – 90
91 – 100
F
E
D
C
B
A
4) Stage a2 (assess)
Assignment:
For this student will submit Lab Assignment before the deadline.
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LAB # 08
Statement Purpose:
In this lab, students will know about the basic concepts of Array data structure,
storing different types of data in arrays, creating arrays of integers, double, Strings and
passing arrays to the methods.
Activity Outcomes:
This lab teaches you the following topics:





Create Arrays
Accessing indexes/location of variables in arrays
Accessing maximum, minimum numbers in arrays
Different array’s operation
Passing arrays to methods
Instructor Note:
As pre-lab activity, read Chapter 7 and 8 from the book (Introduction to JAVA
Programming, Liang, Y.D., 10th Edition (2015), Prentice Hall), and also as given by your
theory instructor.
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1)
StageJ(Journey)
Introduction
Often you will have to store a large number of values during the execution of a program.
Suppose, for instance, that you need to read 100 numbers, compute their average, and
findout how many numbers are above the average. Your program first reads the
numbers andcomputes their average, then compares each number with the average to
determine whetherit is above the average. In order to accomplish this task, the numbers
must all be stored invariables. You have to declare 100 variables and repeatedly write
almost identical code100 times. Writing a program this way would be impractical. So,
how do you solve thisproblem?
An efficient, organized approach is needed. Java and most other high-level languages
providea data structure, the array, which stores a fixed-size sequential collection of
elements ofthe same type. In the present case, you can store all 100 numbers into an
array and access themthrough a single array variable.
Array is a data structure that represents a collection of the same types of data.
The array elements are accessed through the index. The array indices are 0-based, i.e., it
starts from 0 to arrayRefVar.length-1.
•
Declaring arrays:
elementType[] arrayRefVar;
The elementType can be any data type, and all elements in the array will have the same
data type. For example, the following code declares a variable myList that references an
array of double elements.
double[] myList;
•
Creating arrays:
arrayRefVar = new elementType[arraySize];
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2)
Stage a1 (apply)
Lab Activities:
Activity 1:
Create a menu driven program, with the following functionalities: (Note: all of the
functionalities should be created in a single program with following menu options)
1.
Input elements in array. (details of this functionality is given in Step a)
2.
Search element and its location. (details of this functionality is given in
Step b)
3.
Find largest and smallest value in the array. (details of this
functionality is given in Step c)
4.
Copy data. (details of this functionality is given in Step d)
a)
Input 10 elements in the array and display the array. (Note: this should
call two methods Input(int Array[ ] ) and display(int A[ ]) )
b)
Search element is in the array then print “Element found” along with
its location. (Note: this should call two methods Input(int Array[ ]) and
search(intsearchkey, int Array[ ]). You should call the same Input() method that
is called in step a )
c)
Find the largest and the smallest element in array. Then place largest
element on 0th index and smallest element on the last index 9th. (Note: this
should call three methods previously used Input(int Array[]) , Largest(int
Array[]) and Smallest (int Array[])
d)
Copy the contents of one array into another.(Note: this should call two
methods Input(int Array[]) and copydata(int Array[], intcopiedArray[]).
Solution:
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You will get the following output.
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Activity 2:
Write a program which takes 50 characters as input in array and counts the occurrences
of each character.
E.g.
A occurs 2 times
Y occurs 1 time
E occurs 1 time
O occurs 2 times
K occurs 1 time
@ occurs 1 time
……. So on…
Solution:
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You will get the following output.
Activity 3:
Write a program to insert elements in 2D array. Then print the array in matrix form.
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You will get the following output.
Activity 4:
Write a program that reads two 2-D arrays of 3X3 each and Swap their values and then
print both matrices.
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You will get the following output.
Activity 5:
Program below will show the difference between passing a primitive datatype value and
an array reference variable to a method.The program contains two methods for
swapping elements in an array. The first method,named swap, fails to swap two int
arguments. The second method, named swapFirst-TwoInArray, successfully swaps the
first two elements in the array argument.
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You will get the following output.
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3) Stagev(verify)
Home Activities:
1. Forty students were asked to rate the quality of food in the student cafeteria, on a scale of
1 to 10 (1 means awful and 10 means excellent). Place the forty responses in an integer
array and summarize the results of the poll.
2. Write a program which performs the following tasks:
• initialize an integer array of 10 elements in main( )
• Pass the entire array to a function modify( )
• In modify( ) multiply each element of array by 3
• return the control to main( ) and print the new array elements in main( )
3. Write a program to copy the contents of one array into another in the reverse order.
4)
Stagea2(assess)
Lab Assignment and Viva voce
LAB # 09
Statement Purpose:
This lab will teach you about strings in Java. How strings are defined and used Java?
Activity Outcomes:
This lab teaches you the following topics:



How to define strings
How to use strings in problem solving
Using predefined string methods
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
Passing strings to methods
Instructor Note:
As pre-lab activity, read Chapter 9 from the book (Introduction to Java Programming, Brief VersionPrentice Hall (2012) By Y. Daniel Liang), and also as given by your theory instructor.
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1) Stage J (Journey)
Introduction:
Strings, which are widely used in Java programming, are a sequence of characters. In the
Java programming language, strings are objects. The Java platform provides the String
class to create and manipulate strings [Oracle]. String literals are collection of
characters enclosed in double quotation marks. In many programming assignments, you
will be required to accept or process alphabetic or alphanumeric data. For this purpose
you may use strings to get the required results.
The String Class
Java provides a built-in String class which provides a number of useful methods which
may be used to process strings.
Constructing a String
Strings can be constructed in a number of ways as below.
String s=new String(“COMSATS”);
Or
String s=”COMSATS”
We may also take strings as input from user at runtime. For this purpose we may use
next() or nextLine() methods of Scanner class as discussed in the later activities
of this lab session.
Concatenating Strings
Anything added with a string is called string concatenation. For example if we add “abc”
with “xyz”, then the result will be “abcxyz”. Similarly if we add “street” with a mu,eric
integer 1 then the result will be “street1” as below.
“street”+1 will result “street1”.
Strings can also be concatenated by using built-in concat() method as below.
“string1”.concat(“string2”)
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String Built-in Methods
Strings class has a number of useful methods. Some of them are as below.
“string1”.equals(“string2”)
returns true if “string1” and “string2” have same value otherwise
false
“string1”.equalsIgnoreCase(“string2”)
returns true if “string1” and “string2” have same value otherwise
false ignoring the case
“string1”.compareTo(“string2”)
Returns o, positive or negative integer value depending on that
whether string1 is equal to, greater than or less than string2.
“string1”.compareToIgnaoreCase(“string2”)
Returns 0, positive or negative integer value depending on that
whether string1 is equal to, greater than or less than string2
ignoring case.
“string”.length()
Returns length of the string.
“string”.charAt(index)
Returns the character at specified index.
“string”.concat(“string2”)
Concatenates the two strings.
“Pakistan”.substring(0,3)
Returns a 3-charcter long substring starting at index 0.
“Pakistan”.indexOf(“k”)
Returns index of “k” in “Pakistan”, i.e. 2. If the string to find is not
present in the string then returns a negative integer.
“Pakistan”.lastIndexOf(“a”)
Returns last index of “a” in “Pakistan”, i.e. 6 in this example.
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2) Stage a1 (apply)
Lab Activities:
Activity 1:
Write a Java program to accept two strings from user and check that whether they are
same or not.
Solution:
C. Create a new Java file and type the following code.
D. Run the code by pressing F5.
You will get the following output.
Here is another output if the strings are different.
If strings are same but one is given in lowercase and the other in uppercase, then the
output will be as below.
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Activity 2:
Rewrite the last code to accept two strings from user and compare with each other
ignoring case.
Solution:
C. Create a new Java file and type the following code.
D. Run the code by pressing F5.
You will get the following output.
Activity 3:
Write a java program to accept two strings from user and display the smaller string.
Kindly note that smaller does not mean here that it will have less number of characters
in it but you need to compare the strings on the basis of ASCII character. For example,
“ahsan” is less than “zia” as ASCII code of “a” is less than that of “z”.
Solution:
C. Create a new Java file and type the following code.
D. Run the code by pressing F5.
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You will get the following output.
Activity 4:
Write a Java program to accept names of 5 students and sort in ascending order.
Solution:
C. Create a new Java file and type the following code.
D. Run the code by pressing F5.
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You will get the following output.
Activity 5:
Write Java program to accept names of 5 students from user in an array. Pass this array
to a method. The method will sort the names in descending order.
Solution:
C. Create a new Java file and type the following code.
D. Run the code by pressing F5.
You will get the following output.
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3) Stage v (verify)
Home Activities:
Activity 1:
Write a Java program to accept names and marks of 10 students. Display names of
student having maximum marks.
Activity 2:
Write a Java program to accept names and marks of 10 students. Sort this data
according to names in ascending order.
Activity 3:
Write a Java method to accept marks of a student between 0-100 and return the grade
according to the following criteria.
0 - 49
50 – 60
61 – 70
71 – 80
81 – 90
91 – 100
F
E
D
C
B
A
4) Stage a2 (assess)
Assignment:
For this student will submit Lab Assignment before the deadline.
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LAB # 10
Statement Purpose:
This lab will give you practical implementation of method overloading and recursion.
Activity Outcomes:
This lab teaches you the following topics:


Methods overloading
Recursion
Instructor Note:
As pre-lab activity, read Chapters 5 and 20 from the book (Introduction to Java Programming, Brief
Version-Prentice Hall (2012) By Y. Daniel Liang), and also as given by your theory instructor.
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1) Stage J (Journey)
Introduction:
Methods overloading means to define more than one methods having same name but
different signatures in the same class. It enables us to use the same method’s name
multiple time in the same class. The functionality of each method may be different. It is
important to note that the return type of the method has nothing to do with
overloading. The return type may be kept same or different but the number or type of
parameters must be different to implement methods overloading.
Sometimes it may be required that a method should call itself to solve a particular
problem. If this happens then this is called recursion.
Methods Overloading
The important points in methods overloading are as below.
1.
2.
3.
4.
All the methods involved in overloading must be defined in the same class.
Names of all the methods must be same.
Number of parameters should be different.
If number of parameters are same then data type of at least on of them should be
different from other methods.
5. Names of parameters do no matter in methods overloading
6. Return type of methods may be same or different as return type is also not
considered in methods overloading
Recursion
In recursion, a method calls itself. If a method starts calling itself then a kind of loop
starts to happen. You must write some statements to break this loop so recursion stops.
2) Stage a1 (apply)
Lab Activities:
Activity 1:
Write a Java program to have two methods of same name called sum. One of them
should accept two integer values and return their sum. The other sum method should
accept three integer values and return their sum.
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Solution:
E. Create a new Java file and type the following code.
F. Run the code by pressing F5.
You will get the following output.
Here is the modified to code call the method having three parameters.
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The output will be as below.
Activity 2:
Write two methods having name sum. One of them will add two integer values and the
other will add two double values.
Solution:
E. Create a new Java file and type the following code.
F. Run the code by pressing F5.
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You will get the following output.
Activity 3:
Write two methods having name max. One of them will accept an array of integers and
return maximum value. The other will accept an array of strings and return thr string
having maximum number of characters in it.
Solution:
E. Create a new Java file and type the following code.
F. Run the code by pressing F5.
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You will get the following output.
Activity 4:
Write a method to find factorial of an integer using recursion.
Solution:
E. Create a new Java file and type the following code.
F. Run the code by pressing F5.
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You will get the following output.
Activity 5:
Write a Java program to display Fibonacci series by using a recursive method.
Solution:
E. Create a new Java file and type the following code.
F. Run the code by pressing F5.
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You will get the following output.
3) Stage v (verify)
Home Activities:
Activity 1:
Write the following overloaded methods and use them in a Java program.
int multiply(int a, int b)
double multiply(double x, double y)
float multiply(float a, float b)
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Activity 2:
Write two overloaded methods having name sort. One of them will accept an array of
strings and sort them in descending order. The other will accept an array of integer
values and will sort them in descending order.
Activity 3:
Write a recursive method to build tower of Hanoi.
4) Stage a2 (assess)
Assignment:
For this student will submit Lab Assignment before the deadline.
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LAB # 11
Statement Purpose:
In this lab you will experiment with the Java Input/Output components by implementing two
programs that read input from a file and write output to a file.
The java.io package contains nearly every class you might ever need to perform input and output
(I/O) in Java. All these streams represent an input source and an output destination. The stream in
the java.io package supports many data such as primitives, object, localized characters, etc.
Activity Outcomes:
Student will be able to:
1.
2.
3.
4.
Describe the concept of an I/O stream
Explain the difference between text files and binary files
Save data
Read data
Instructor Note:
Java: An Introduction to Problem Solving and Programming, Savitch, W., 6th Edition (2012),
Addison-Wesley
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1)
Stage J (Journey)
Introduction
The character input and output shown so far has used the pre-defined “standard” streams
System.in and System.out. Obviously in many real applications it is necessary to access named
files. In many programming languages there is a logical (and practical) distinction made between
files that will contain text and those while will be used to hold binary information. Files
processed as binary are thought of as sequences of 8- bit bytes, while ones containing text
model sequences of characters.
Java uses names typically based on the word Stream for binary access, and Reader and Writer
for text. So when you read the documentation expect to find two broadly parallel sets of
mechanisms, one for each style of access.
2)
Stage a1 (apply)
Lab Activities:
Activity 1: creates InputStreamReader to read standard input stream until
the user types a "q".
Solution:
import java.io.*;
public class ReadConsole {
public static void main(String args[]) throws IOException {
InputStreamReader cin = null;
try {
cin = new InputStreamReader(System.in);
System.out.println("Enter characters, 'q' to quit.");
char c;
do {
c = (char) cin.read();
System.out.print(c);
} while(c != 'q');
}finally {
if (cin != null) {
cin.close();
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}
}
}
}
Activity 2:
Write a java program to demonstrate InputStream and OutputStream
Solution:
import java.io.*;
public class fileStreamTest {
public static void main(String args[]) {
try {
byte bWrite [] = {11,21,3,40,5};
OutputStream os = new FileOutputStream("test.txt");
for(int x = 0; x < bWrite.length ; x++) {
os.write( bWrite[x] );
// writes the bytes
}
os.close();
InputStream is = new FileInputStream("test.txt");
int size = is.available();
for(int i = 0; i < size; i++) {
System.out.print((char)is.read() + "
");
}
is.close();
}catch(IOException e) {
System.out.print("Exception");
}
}
}
Activity 3:
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A java program to show that a method called to read characters, and that it
returns the integer -1 at end of file.
Solution:
import java.io.*;
public class InputOP1 {
public static void main(String args[]) throws IOException {
Reader r = new FileReader("filename");
int c;
while ((c = r.read()) != -1)
{ System.out.printf("Char code %x is \"%<c\"%n", c);}
r.close();
}
}
Activity 3:
Write a java program by using list( ) method provided by File object to list
down all the files and directories available in a directory.
Solution:
import java.io.File;
public class ReadDir {
public static void main(String[] args) {
File file = null;
String[] paths;
try {
// create new file object
file = new File("/tmp");
// array of files and directory
paths = file.list();
// for each name in the path array
for(String path:paths) {
// prints filename and directory name
System.out.println(path);
}
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}catch(Exception e) {
// if any error occurs
e.printStackTrace();
}
}
}
Activity 4:
Write a java program to compare paths of two files?
Solution:
import java.io.File;
public class Main {
public static void main(String[] args) {
File file1 = new File("C:/File/demo1.txt");
File file2 = new File("C:/java/demo1.txt");
if(file1.compareTo(file2) == 0) {
System.out.println("Both paths are same!");
} else {
System.out.println("Paths are not same!");
}
}
}
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Activity 5:
Write a java program to create a new file?
Solution:
import java.io.File;
import java.io.IOException;
public class Main {
public static void main(String[] args) {
try {
File file = new File("C:/myfile.txt");
if(file.createNewFile())System.out.println("Success!");
else System.out.println ("Error, file already exists.");
}
catch(IOException ioe) {
ioe.printStackTrace();
}
}
}
Activity 6:
Write a java program to create a new file (another way)?
Solution:
import java.io.IOException;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.Arrays;
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import java.util.List;
public class JavaApplication1 {
public static void main(String[] args) throws IOException {
createFileUsingFileClass();
createFileUsingFileOutputStreamClass();
createFileIn_NIO();
}
private static void createFileUsingFileClass() throws IOException {
File file = new File("c://testFile1.txt");
//Create the file
if (file.createNewFile()) {
System.out.println("File is created!");
} else {
System.out.println("File already exists.");
}
//Write Content
FileWriter writer = new FileWriter(file);
writer.write("Test data");
writer.close();
}
private static void createFileUsingFileOutputStreamClass() throws IOException {
String data = "Test data";
FileOutputStream out = new FileOutputStream("c://testFile2.txt");
out.write(data.getBytes());
out.close();
}
private static void createFileIn_NIO()
throws IOException {
String data = "Test data";
Files.write(Paths.get("c://testFile3.txt"), data.getBytes());
List<String> lines = Arrays.asList("1st line", "2nd line");
Files.write(Paths.get(
"file6.txt"), lines, StandardCharsets.UTF_8,
StandardOpenOption.CREATE, StandardOpenOption.APPEND);
}
}
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Activity 7:
Write a java program to get last modification date of a file?
Solution:
import java.io.File;
import java.util.Date;
public class Main {
public static void main(String[] args) {
File file = new File("Main.java");
Long lastModified = file.lastModified();
Date date = new Date(lastModified);
System.out.println(date);
}
}
Stage v (verify)
Home Activities:
Activity 1: Write a java program to create a file in a specified directory?
Activity 2: Write a java program to check a file exist or not?
3)
Stage a2 (assess)
Assignment:
1) Write a java program to make a file read-only?
2) Write a java program to rename a file?
LAB # 12
Statement Purpose:
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In this lab you will experiment with the Java Input/Output components by implementing two
programs that read input from a file and write output to a file.
The java.io package contains nearly every class you might ever need to perform input and
output (I/O) in Java. All these streams represent an input source and an output destination. The
stream in the java.io package supports many data such as primitives, object, localized
characters, etc.
Activity Outcomes:
Student will be able to:
1) Describe the concept of an I/O stream
2) Explain the difference between text files and binary files
3) Save data
4) Read data
Instructor Note:
Java: An Introduction to Problem Solving and Programming, Savitch, W., 6th Edition (2012),
Addison-Wesley
1)
Stage J (Journey)
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2)
Stage a1 (apply)
Lab Activities:
Activity 1:
Write a java program to get a files size in bytes?
Solution:
import java.io.File;
public class Main {
public static long getFileSize(String filename) {
File file = new File(filename);
if (!file.exists() || !file.isFile()) {
System.out.println("File doesn\'t exist");
return -1;
}
return file.length();
}
public static void main(String[] args) {
long size = getFileSize("c:/java.txt");
System.out.println("Filesize in bytes: " + size);
}
}
Activity 2:
Write a java program to get a files size in bytes?
Solution:
import java.io.File;
public class Main {
public static long getFileSize(String filename) {
File file = new File(filename);
if (!file.exists() || !file.isFile()) {
System.out.println("File doesn\'t exist");
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return -1;
}
return file.length();
}
public static void main(String[] args) {
long size = getFileSize("c:/java.txt");
System.out.println("Filesize in bytes: " + size);
}
}
Activity 3:
Write a java program to change the last modification time of a file?
Solution:
import java.io.File;
import java.util.Date;
public class Main {
public static void main(String[] args) throws Exception {
File fileToChange = new File ("C:/myjavafile.txt");
fileToChange.createNewFile();
Date filetime = new Date (fileToChange.lastModified());
System.out.println(filetime.toString());
System.out.println (fileToChange.setLastModified
(System.currentTimeMillis()));
filetime = new Date (fileToChange.lastModified());
System.out.println(filetime.toString());
}
}
Activity 4:
Write a java program to create a temporary file?
Solution:
import java.io.*;
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public class Main {
public static void main(String[] args) throws Exception {
File temp = File.createTempFile ("pattern", ".suffix");
temp.deleteOnExit();
BufferedWriter out = new BufferedWriter (new FileWriter(temp));
out.write("aString");
System.out.println("temporary file created:");
out.close();
}
}
Activity 5:
Write a java program to append a string in an existing file?
Solution:
import java.io.*;
public class Main {
public static void main(String[] args) throws Exception {
try {
BufferedWriter out = new BufferedWriter(new FileWriter("filename"));
out.write("aString1\n");
out.close();
out = new BufferedWriter(new FileWriter("filename",true));
out.write("aString2");
out.close();
BufferedReader in = new BufferedReader(new FileReader("filename"));
String str;
while ((str = in.readLine()) != null) {
System.out.println(str);
}
}
in.close();
catch (IOException e) {
System.out.println("exception occoured"+ e);
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}
}
}
3)
Stage v (verify)
Home Activities:
Activity 1: Write a java program to copy one file into another file?
Activity 2: Write a java program to delete a file?
4)
Stage a2 (assess)
Assignment:
1) Write a java program to read a file?
2) Write a java program to write into a file?
LAB # 13
Statement Purpose:
An exception is an object that signals the occurrence of an unusual event during the execution
of a program. The process of creating this object that is generated an exception is called
throwing an exception.
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Activity Outcomes:
1) Describe the notation of exception handling
2) React correctly when certain exceptions occur
3) Use Java’s exception-handling facilities effectively in classes and programs
Instructor Note:
Java: An Introduction to Problem Solving and Programming, Savitch, W., 6th Edition (2012),
Addison-Wesley
1) Stage J (Journey)
Introduction
Unit testing can be done in two ways − manual testing and automated testing.
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Manual Testing
1. Executing a test cases manually without any tool support is known as manual testing.
2. Time-consuming and tedious − Since test cases are executed by human resources, it is very
slow and tedious.
3. Huge investment in human resources − As test cases need to be executed manually, more
testers are required in manual testing.
4. Less reliable − Manual testing is less reliable, as it has to account for human errors.
5. Non-programmable − No programming can be done to write sophisticated tests to fetch
hidden information.
Automated Testing
6. Taking tool support and executing the test cases by using an automation tool is known as
automation testing.
7. Fast − Automation runs test cases significantly faster than human resources.
8. Less investment in human resources − Test cases are executed using automation tools, so
less number of testers are required in automation testing.
9. More reliable − Automation tests are precise and reliable.
10. Programmable − Testers can program sophisticated tests to bring out hidden information.
A Unit Test Case is a part of code, which ensures that another part of code (method) works as
expected. To achieve the desired results quickly, a test framework is required. JUnit is a perfect unit
test framework for Java programming language.
A formal written unit test case is characterized by a known input and an expected output, which is
worked out before the test is executed. The known input should test a precondition and the
expected output should test a post-condition.
There must be at least two unit test cases for each requirement − one positive test and one negative
test. If a requirement has sub-requirements, each sub-requirement must have at least two test cases
as positive and negative.
2)
Stage a1 (apply)
Lab Activities:
Activity 1:
Write a java program that catches arithmetic exception.
Solution:
class Example1 {
public static void main(String args[]) {
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int num1, num2;
try {
// Try block to handle code that may cause exception
num1 = 0;
num2 = 62 / num1;
System.out.println("Try block message");
} catch (ArithmeticException e) {
// This block is to catch divide-by-zero error
System.out.println("Error: Don't divide a number by zero");
}
System.out.println("After try-catch block in Java.");
}
}
Activity 2:
A java program for an array declared with 2 elements. Then the code tries to
access the 3rd element of the array which throws an exception.
Solution:
import java.io.*;
public class Example2{
public static void main(String args[]) {
try {
int a[] = new int[2];
System.out.println("Access element three :" + a[3]);
}catch(ArrayIndexOutOfBoundsException e) {
System.out.println("Exception thrown :" + e);
}
System.out.println("Out of the block");
}}
Activity 3:
Java program to access the index in an array that is not present in it.
Solution:
public class Example3{
public static void main(String args[]) {
int a[] = new int[2];
try {
System.out.println("Access element three :" + a[3]);
}catch(ArrayIndexOutOfBoundsException e) {
System.out.println("Exception thrown :" + e);
}finally {
a[0] = 6;
System.out.println("First element value: " + a[0]);
System.out.println("The finally statement is executed");
}
}
}
Activity 4:
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Java program for multiple try catch blocks.
Solution:
class Example4{
public static void main(String args[]){
try{
int a[]=new int[7];
a[4]=30/0;
System.out.println("First print statement in try block");
}
catch(ArithmeticException e){
System.out.println("Warning: ArithmeticException");
}
catch(ArrayIndexOutOfBoundsException e){
System.out.println("Warning: ArrayIndexOutOfBoundsException");
}
catch(Exception e){
System.out.println("Warning: Some Other exception");
}
System.out.println("Out of try-catch block...");
}
}
Activity 5:
Java program for nested try loops
Solution:
class Example5{
public static void main(String[] args) {
try {
int arr[]={5,0,1,2};
try {
int x=arr[3]/arr[1];
}
catch(ArithmeticException ae){
System.out.println("divide by zero");
}
arr[4]=3;
}
catch(ArrayIndexOutOfBoundsException e) {
System.out.println("array index out of bound exception");
} }}
3)
Stage v (verify)
Home Activities:
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Activity 1:
Create your own exception sub class simply by extending
java Exception class. You can define a constructor for your Exception sub
class (not compulsory) and you can override the toString() function to
display your customized message on catch.
4)
Stage a2 (assess)
Assignment:
Write a statement that will throw an exception of type Exception if the value
of the String variable named status is “bad”. The string recovered by
getMessage should be “Exception thrown: Bad Status.” You need not write
the try block and catch block.
LAB # 14
Statement Purpose:
One of the secrets of the low latency is that each implementation can generate a custom built
fix engine based exactly on the schema it requires.
Activity Outcomes:
1) Describe the notation of exception handling
2) React correctly when certain exceptions occur
3) Use Java’s exception-handling facilities effectively in classes and programs
Instructor Note:
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Java: An Introduction to Problem Solving and Programming, Savitch, W., 6th Edition (2012),
Addison-Wesley
1)
2)
Stage J (Journey)
Stage a1 (apply)
Lab Activities:
Activity 1:
Java program that extends java Exception class.
Solution:
class MyException1 extends Exception1
{
private int ex;
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MyException1(int a)
{
ex=a;
}
public String toString()
{
return "MyException1[" + ex +"] is less than zero";
}
}
class Test
{
static void sum(int a,int b) throws MyException1
{
if(a<0)
{
throw new MyException1(a);
}
else
{
System.out.println(a+b);
}
}
public static void main(String[] args)
{
try
{
sum(-10, 10);
}
catch(MyException1 me)
{
System.out.println(me);
}
}
}
Activity 2:
NOTE: If Super class method throws an exception, then Subclass overriden method can throw
the same exception or no exception, but must not throw parent exception of the exception
thrown by Super class method.
It means, if Super class method throws object of NullPointerException class, then Subclass
method can either throw same exception, or can throw no exception, but it can never throw
object of Exception class (parent of NullPointerException class).
Subclass overridden method with exception.
Solution:
import java.io.*;
class Super
{
void show() throws Exception
{ System.out.println("parent class");
}
}
public class Sub extends Super {
void show() throws Exception
//Correct
{ System.out.println("child class"); }
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public static void main(String[] args)
{
try {
Super s=new Sub();
s.show();
}
catch(Exception e){}
}
}
Activity 3:
Subclass overridden method with no exception.
Solution:
import java.io.*;
class Super
{
void show() throws Exception
{ System.out.println("parent class");
}
}
public class Sub extends Super {
void show()
//Correct
{ System.out.println("child class"); }
public static void main(String[] args)
{
try {
Super s=new Sub();
s.show();
}
catch(Exception e){}
}
}
Activity 4:
Subclass overridden method with parent Exception.
Solution:
import java.io.*;
class Super
{
void show() throws ArithmeticException
{ System.out.println("parent class");
}
public class Sub extends Super {
void show() throws Exception
{ System.out.println("child class"); }
}
//Cmpile time Error
public static void main(String[] args)
{
try {
Super s=new Sub();
s.show();
}
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catch(Exception e){}
}
}
Activity 5:
Using ObjectInputStream to Read from a File
Solution:
public class BinaryInput
{
public static void main(String[] args)
{
String fileName = "numbers.dat";
try
{
ObjectInputStream inputStream =
new ObjectInputStream(new FileInputStream(fileName));
System.out.println("Reading the nonnegative integers");
System.out.println("in the file " + fileName);
int anInteger = inputStream.(readInt);
while (anInteger >= 0)
{
System.out.ptintln(anInteger);
anInteger = inputStream.readInt();
}
System.out.println("End of reading from file.");
inputStream.close();
}
catch(FileNotFoundException e)
{
System.out.println("Problem opening the file " + fileName);
}
catch(EOFException e)
{
System.out.println("Problem reading the file " + fileName);
System.out.println("Reached end of the file.");
}
catch(IOException e)
{
System.out.println("Problem reading the file " + fileName);
}
}}
3)
Stage v (verify)
Home Activities:
Activity 1: Write java code to create an input stream of type ObjectInputStream that is
named from File and is connected to a file named stuff.data.
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Activity 2: Write a Java program that asks the user for the name of a binary file and writes
the first data item in that file to the screen. Assume that the first data item is a string that was
written to the file with method WriteUTF.
4)
Stage a2 (assess)
Assignment:
Write a complete Java program that asks the user for a file name, tests whether the file exists,
and if the file does exist, ask the user whether or not it should be deleted and then does as the
user requests.
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