LECTURE
Introduction to Programming Logic and Technique
DTNhung – NIIT HAIPHONG
Start-up
1.
Can you list a serial generation language
programming?
2.
The vocabulary of commonly spoken
communication is ________ the vocabulary of a
programming language?
a. Greater than b. Less than c. Equal to
3.
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What programming language do you like?
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Solutions
1.
2.
3.
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Generations of programming languages

1st generation is machine language.

2nd generation is assembly language.

3rd generation is high-level languages such
as BASIC, Pascal, C…
a. Greater than
Suggestions: Assembly, Pascal, C, C++, Visual
Basic, Visual C++, Java, Delphi, ASP, JSP,
Pearl…
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Introduction to Programming Logic and Technique

Chapter 1


Chapter 2


Representing the logic of Programming using Pseudocodes.
Chapter 3


Introducing to Programming Concept
Representing the logic of Programming using Flowcharts
Chapter 4

Understanding Iterations and Implementing Modular
Programming
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Introducing to Programming Concept


Computer follows an I-P-O
cycle. It needs set of instructions
called program to specify the
input required, process to be
followed, and the output
Input
required.
Program is written in a specific
language called Programming
language, so that computer can
understand the instructions.
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Process
Output
Feedback
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Introducing to Programming Concepts
A set of instructions to perform a particular job is called a program.
Therefore, for each job that you want the computer to perform, you
require a separate program. Instructions in a program can be:
Sequential: Instructions that are executed one after the other.
„
Decision Making: Instructions that evaluate an expression (relation or
condition) first and then, depending upon whether the value of the expression is
'true' (non-zero) or 'false' (zero), it transfers the control to a particular
statement.
 „Iterative: Instructions that are executed repeatedly, depending on the value of
an expression (relation or condition)

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Programming Languages

MACHINE LANGUAGE

A sequence of 0s and 1s can be used to
describe any physical operation that the
computer performs. Therefore, a computer
system uses a number system that consists
of only two digits, 0 and 1. This number
system is known as the binary number
system.
The language that the computer
understands is called the machine
language.
It is doubtful if you would be comfortable
writing a program in machine language. It
is certainly difficult for anybody to
remember instructions in the form of 0s
and 1s.


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Command
Machine code
ADD
00000001
SUBTRACT
00000010
MULTIPLY
00000100
DIVIDE
00001000
READ FROM
KEYBOARD
00010000
WRITE ON
SCREEN
00100000
WRITE ON
PRINTER
01000000
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Machine language
1000 010 11 1
01100101 011
0001 0 1 010 1

No need translater
(compiler)
The binary number system uses
the base of 2. For example, 101
in the binary system is equal to 5
in the decimal system. The
conversion can be done as:
101=1*22 + 0*21+ 1* 20 =1*4 +
0*2 + 1*1 = 4 + 0 + 1=5
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Assembly language
LD Ax, 9
LD Bx, 10
ADD Ax,Bx
LD (100),Ax
JMP Bx
HLT
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


Assembler
100 0 00 11
11 000 0 0
1 00 0 111
In the above program:
The line number one loads register Ax with the value, 9.
The line number two loads register Bx with the value, 10.
The line number three adds the value of register Bx to the value of register Ax.
The line number four stores the value of register Ax in the main memory
location, 100.
The line number five uses JMP to jump to register Bx to transfer the control to
register Bx.
The line number six stops the program execution.
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High level language



A high-level programming language consists of a set of
instructions, which are represented using simple English words.
So, when you want the computer to display the output on the
screen, you type the instruction ‘WRITE ON SCREEN’ and not
‘00100000’.
There are many high-level programming languages available,
such as C, C++, and Java. Each language has its own advantages.
Programming languages also have a vocabulary, which is referred
to as the set of keywords of that language, and a grammar, which
is referred to as the syntax.
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High level language


As stated earlier, a program written in any programming language is a
set of logically related instructions. These instructions have two parts, as
shown in the following figure:
The two parts of a programming language instruction are:

„Operation code (opcode): This part instructs a computer about the
operation to be performed.
 „
Operand: This part instructs the computer about the location of the data on
which the operation specified by the opcode is to be performed.
Operation code
(Opcode)

Operand
(Address)
For example, in the instruction Add A and B, Add is the opcode and A
and B are operands
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High level language
begin
numeric nNumber1, nNumber2, nNumber3
nNumber1 = 15
nNumber2 = 2
nNumber3 =nNumber1% nNumber2
display nNumber3
end
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Algorithm


An algorithm is a sequence of steps required to solve a problem
An algorithm follows the I-P-O cycle to solve the problem.
The two levels of algorithm are:
Macro-level: An algorithm that contains brief steps about a
process is called a macro-level algorithm.
Micro-level: An algorithm that contains detailed steps about
a process is called a micro-level algorithm.
An algorithm is represented using tools such as:
Pseudocode
Flowcharts
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Algorithm

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An algorithm has the following five characteristics:
 An algorithm ends after a fixed number of steps.
 Each step in an algorithm clearly specifies the action to
be performed.
 The steps in an algorithm specify basic operations. These
operations could include calculations, input/output
operations, and comparisons.
 An algorithm accepts input data, in a defined format,
before it can be processed.
 An algorithm generates one or more outputs after the
input is processed. The resultant information termed as
output can be displayed or stored for future reference.
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Pseudocode
Vocabulary









• Operator
Declare (variables, literals, procedures,
functions…): khai báo
Assign: gán giá trị
Function: hàm
•
Procedure: thủ tục
•
Flowchart: lược đồ thuật toán
Pseudocode /sj:udoucode/: mã giả •
Variable: biến
•
Constant/literal: hằng
Expression: biểu thức
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Arithmetic: toán tử toán học
Relational: toán tử quan hệ
Logical: toán tử logic
Operand: toán hạng
Precedence: mức ưu tiên
Comment: chú thích
Dry run table: chạy thô
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Algorithm - Pseudocode
Begin
numeric nNum1, nResult
numeric nCons = 10
Display ‘Enter the first number’
Accept nNum1
nResult = (nNum1 * nCons) / 73
If nResult > nCons
Display “ the number is greater than 10’
else
Display “ The number is less than 10’
Display nResult
End
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Pseudocode
Advantages of pseudocode are:
It is easier and faster to write as it uses English like statements .
 It does not need to be rewritten if any changes are made because each step is
independent and may be modified without altering the other steps.
 It can be converted to a program using any programming language.

Disadvantages of pseudocode are:


Pseudocode does not provide a graphical representation of an algorithm.
Pseudocode depicting too many nested conditions may be difficult to
understand.
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Vocabulary - Pseudocode



Declare (variables, literals, procedures, functions…): khai báo
Assign (values to variables): gán
Operator







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Arithmetic: toán tử toán học
Relational: toán tử quan hệ
Logical: toán tử logic
Operand: toán hạng
Operator precedence: toán tử ưu tiên
Comment: chú thích
Dry run table: chạy thô
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Pseudocode
Begin
numeric nNum1, nResult // Declare variables
numeric nCons = 10// Direct assignment, initialize first
Display ‘Enter the first number’
Accept nNum1 //Accept statement
nResult = (nNum1 * nCons) / 73
If nResult > nCons
Display “ the number is greater than 10’
else
Display “ The number is less than 10’
Display nResult
value
End
==================================
Variable: nNum1, nResult
Constant: nCons
Expression: nResult =(nNum1*nCons)/73
//: Comment
Char, numeric: tupe of data
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Flowchart
A flowchart is a graphical
representation of the steps
to be ollowed for solving a
problem.
It consists of a set of
symbols.
Each symbol represents a
specific activity.
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Flowchart
Advantages of Flowcharts are:
Flowcharts are a better method of communicating logic.
The flowcharts help in analyzing the problems effectively .
The flowcharts act as a guide during the program development phase.
It is easier to debug errors in logic using a flowchart.
The flowcharts help in maintaining the programs.
Disadvantages of Flowcharts are:
A lengthy flowchart may extend over multiple pages, which reduces readability.
As flowcharts symbols cannot be typed, drawing a flowchart using any graphic tool
is a time consuming process.
The changes made to a single step may cause redrawing the entire flowchart.
A flowchart representing a complex algorithm may have too many flow lines. This
reduces readability, and it is time-consuming to draw and understand the logic
Readability.
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Pseudocode
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Keywords in Pseudocode
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Keyword in Pseudocode
begin … end: These keywords are used to start and finish pseudocode.
Begin is the first line and end is the last line of pseudocode.
accept: This keyword is used to obtain an input from a user.
display: This keyword is used to present a result or an output.
if … else… endif: These keywords are used in decision-making.
//: Comment
Do … while, for …, repeat … until: Represent loop
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Using Pseudocodes to Represent Sequential Code
The pseudocode for adding two numbers is as follows:
// starting the pseudocode
begin
// input consists of accepting two numbers
accept first_number, second_number
// process of adding the two numbers
compute sum as first_number + second_number
// output for displaying the sum
display ‘The sum of given two numbers is’ sum
// ending the pseudocode
end
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Variables and Constants
The internal memory consists of different locations in which
data is stored.
A computer needs to identify the memory locations to be able to
retrieve values from or store values in them.
A variable refers to the memory location whose value changes
during the program execution.
A constant refers to the memory location whose value does not
change during the program execution.
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Variables and Constant


You need to declare a variable before using it in a program.
The declaration of a variable assigns a name to the variable and specifies the type of data
the variable can store.
Naming conventions:




The first letter of the variable name might indicate the data type of the variable: cName
and nAge
The variable name should clearly describe the purpose of a variable: nScore
The variable name should not contain an embedded space or symbols such as ! @ # $ %
^ & * ( ) { } [ ] . , : ; “ ‘ / and \. You can use an underscore when a space is required in a
variable name, for example, nBasic_Salary.
If a variable name consists of multiple words without spaces in between, capitalize the
first letter of each word for readability. Some examples are nTotalScore and
nSumOfSquares.
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Variables and Constant
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Data Types
Numeric:
Numeric variables can contain only numbers.
These variables can be used in arithmetic operations .
Character:
Character variables can contain any combination of letters, numbers, and special
characters.
These variables cannot be used for calculation.
Let us look to the code of accepting two numbers and displaying the sum with the
data type declarations.
begin
numeric nNum1, nNum2, nSum //declaring variables
accept nNum1
accept nNum2
nSum = nNum1 + nNum2
display nSum
end
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Assign values
The variables can be assigned values in the following two methods:
Direct assignment
Accept Statement
In the direct assignment method, values can be assigned to variables using the
equal to (=) sign, as shown in the following syntax:
variable_name=value
Examples:
numeric nHeight, nAge, nCounter
character cCode
nHeight = 172
nAge = 35
nCounter = 0
cCode = “XYZ”
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Assign values
Values can be assigned to variables using the accept statement, as shown in the
following syntax.
accept variable_name
Examples:
character cName
numeric nAge
display “Enter your name”
accept cName
display “Enter your age”
accept nAge
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Variables and Constant
Identify the variable and constant data in the following situation.
Each day, the courier service delivers some letters. The number of
letters is different each day. Regardless of the number of letters
delivered by the courier service, they are paid a carrying charge of
$5.
Variable:
Constant:
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Operators
Arithmetic: +, -, *, /, %
 Relational: >, <. >=, <=, =, !=
 Logical: AND, OR, NOT
Bảng chân trị (chân lý)

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X
Y
AND(X,Y)
OR (X,Y)
NOT(X)
0
0
0
0
1
0
1
0
1
1
1
0
0
1
0
1
1
1
1
0
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Problem 1

Create the pseudocode to accept item name, price, and quantity.
You need to calculate value as the product of price and quantity,
and display the calculated value and the item name using
variables.
Answer:
begin
accept cItem_name, nPrice, nQuantity,
nSale_value
nSale_value = nPrice * nQuantity
display cItem_name
display nSale_value
end
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Priority - Precedence
Operator
Description
()
!
*
/
%
+
<
<=
Parentheses
Logical NOT
Multiplication
Division
Modulo division
Addition
Subtraction
Less than
Less than or equal to
>=
Greater than or equal to
>
=
!=
AND
OR
Greater than
Equal to
Not equal to
Logical AND
Logical OR
Associativity
Precedence
Level
1
2
Left to right
3
Left to right
4
Left to right
5
Left to right
6
Left to right
Left to right
7
8
Operator Precedence
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Conditional Execution
Many problems require decisions to be made.
All decisions may or may not state an action to be taken if
the condition is false.
The following types of decision-making constructs can be
used in an algorithm.
if constructs
switch…case constructs
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Conditional Execution
In simple if construct, if the condition specified is true,
the statements contained within the if block are executed.
Pseudocode segment to represent the simple if constructs
as follows:
if <condition>
begin
<statements to be executed if
condition is true>
end
endif
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Conditional Execution
In the if...else construct, the statements within the if block are
executed for condition being true and the statements within the
else block are executed for condition being false.
if <condition>
begin
<statements
condition
end
else
begin
<statements
condition
end
endif
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to be executed if
is true>
to be executed if
is false>
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If Construct
Problem Statement 1:
Accept two numbers and print the larger of the two numbers.
Solution:
begin
numeric nNum1, nNum2
accept nNum1
accept nNum2
if nNum1 = nNum2
begin
display “The numbers are equal”
end
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If Construct
else
if nNum1>
begin
display
end
else
begin
display
end
endif
endif
end
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nNum2
nNum1
nNum2.
// end of second if statement
// end of first if statement
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If Construct
Problem Statement 2:
Print the value of nX only if the value of nX is greater than 10 and nX is an even
number.
Solution:
begin
numeric nX
accept nX
if nX > 10
//first if-statement
begin
if nX % 2 =0
//second if-statement
display nX
endif
// end of second if-statement
end
endif
//end of first if statement
end
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If Construct
Problem Statement 3:
To decide about the discount percentage on a TV, the sales person needs to
check the type of TV. If the TV is Black and White [B], the discount will be 5
percent of the selling price. If the type of TV is colored [C], then he has to
verify the size of TV screen. For 14 inches screen, discount is 8 percent of the
selling price and for 21 inches screen, the discount is 10 percent of the selling
price. Write a pseudocode to show the discount percentage.
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If Construct
Solution:
begin
numeric nScreen, nDiscount, SP
character cType
accept nType
accept nScreen
accept SP
if cType = ‘B’
// first if statement
begin
compute nDiscount as 5% of SP
end
else
if cType = ‘C’ // second if statement
begin
if nScreen =14 // third if statement
begin
compute nDiscount as 8% of SP
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end
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If Construct
else
begin
if nScreen = 21
// fourth if statement
begin
compute nDiscount as 10% of SP
end
endif
// end of fourth if statement
end
endif
// end of third if statement
end
endif
// end of second if statement
endif
// end of first if statement
end
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The switch…case construct
The switch…case construct enables you to make a decision by selecting from
number of choices. The pseudocode of the switch…case construct is as follows:
switch (expression)
begin
case constant 1:
execute these statements
break
case constant 2:
execute these statements
break
default:
execute these statements
end
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Problem 1
Consider the following problem statement for switch…case construct.
Amy is writing the algorithm for automated telephone call transfer to various
departments of the company such as Marketing, Finance, Customer Care, Human
Resource (HR), and Information. Write the solution using Pseudocode.
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Problem 1
begin
numeric nCall
display “If you want to get connected to Marketing
department, press 1, Finance
department press 2, Customer Care
department press 3, HR department press 4.
If you are not sure press any number other
than 1 to 4, the call will be transferred to Information
department”
accept nCall
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Problem 1
switch (nCall)
begin
case 1: //case 1 begins
Transfer call to the Marketing department
break
case 2: //case 2 begins
Transfer call to the Finance department
break
case 3: //case 3 begins
Transfer call to the Customer Care department
break
case 4: //case 4 begins
Transfer call to the HR department
break
default: //if none of the cases match, the
//following line is executed
Transfer call to the Information department
end
end
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Vocabulary - Programming








Decision-making construct: cấu trúc ra quyết định
Loop construct: cấu trúc lặp
Procedure: thủ tục
Function: hàm
to invoke: triệu gọi
Parameter: tham số
scope (local, global): phạm vi biến
modular approach of programming: lập trình tiếp cận theo
hướng chia module
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Problem Statement 1:
Problem Statement 1:
Write a pseudocode to display the sum of two numbers by using
variables.
Solution:
begin
accept nNum1 //assigning values to variables
accept nNum2
nSum = nNum1 + nNum2
display nSum
end
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Problem Statement 2
Problem Statement 2:
Write a pseudocode where interest is calculated and displayed
for the given balance and rate.
Solution:
begin
//start
accept Name, Balance, Rate
//input
compute Interest as Balance x Rate //process
display Name and Interest
//output
end
//end
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Problem Statement 3
Problem Statement 3:
Write a pseudocode where a number is incremented by 1
Solution:
begin
accept Number
compute Number as Number + 1
display Number
end
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//starting
//input
//process
//output
//end
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Problem 4:
Given: nNum1 = 5, nNum2 = 6
Swap their value together.
Bình
Bình
Bình
Bình
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1
1
1
1
Numeric
nNum1 =
nNum2 =
nSwap =
nSwap =
nNum1 =
nNum2 =
nNum1, nNum2, nSwap
5
6
0
nNum1
nNum2
nSwap
Bình rỗng
Bình rỗng
Bình rỗng
Bình rỗng
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Bình
Bình
Bình
Bình
2
2
2
2
53
A Problem 5:
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Flowchart
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Problem-solving using Flowcharts
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Problem-solving using Flowcharts
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Drawing
Flowchart
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Rules of Flowcharting
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






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The entire logic of a flowchart should be represented using the standard symbols.
„The flowchart should be clear, precise, and easy to follow.
„Flowcharts can have only one start point and one end point.
The steps in a flowchart should follow top-to-bottom or left-to-right approach.
All necessary inputs should be listed out in logical order.
The start and stop symbols should have only a single flow line.
The input, process, output, and display symbols should have two flow lines
connecting to the previous symbol and to the next symbol.
The decision symbol should have one flow line connecting to the previous symbol
but two flow lines connecting to the next symbol for each possible solution such as
Yes/No, Y/N, True/False.
If too many flow lines make the flowchart complex, it is better to use connector
symbols to reduce the number of flow lines.
Flowcharts should use page connectors if they extend over multiple pages.
It is useful to test the logic of flowchart by passing through it with sample test data.
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Conditional Execution using Flowchart
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Conditional Execution using Flowchart
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Conditional Execution using Flowchart
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Nested If- Statements in Flowchart
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Nested If- Statements in Flowchart
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Switch - case
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Interation


One of the most important characteristics of a computer is its
ability to execute a series of instructions repeatedly. This ability of
the computer gives you the flexibility to control the number of
times a task is to be repeated.
The following types of loops can be used in a pseudocode:




„while loop
„repeat…until loop
„for loop
„goto
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For loop
The for loop:
The for loop is used when the number of iterations of the loop is known before the
control enters the loop.
The for loop consists of the following three parts separated by semicolons.
Initialization expression: The numeric variable is initialized
using a value.
Evaluation expression: The condition is tested at the
beginning of iteration of the loop. When the expression
evaluates to false, the loop terminates.
Increment/decrement expression: The value of the variable
is increased.
In a for loop, initializing a variable, evaluating a condition, and incrementing
the value of the variable are all specified in one statement.
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For loop
begin
initialize the index
for test the index
begin
increment the index
//perform the statements if the test is true
end
endfor
//end of for loop
//perform the statements if the test is false
end
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For Loop
The pseudocode representation of a for loop is as follows:
begin
initialize the index
for test the index
begin
increment the index
// perform the statements if the test is true
end
endfor
//end of for loop
// perform the if the test is false
end
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Problem Statement 1
Problem Statement 1:
Draw a flowchart to calculate the sum of 10 numbers entered by the user.
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The while Loop
:
:
while (condition)
begin
:
:
end
:
:
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Problem 2
begin
numeric nMarks, nTotal, nCounter, nAvg
nMarks = 0
nTotal = 0
nCounter = 0
nAvg = 0
while (nCounter < 30) //while the condition is true
begin
display “Enter the total marks of a student”
accept nMarks
nTotal = nTotal + nMarks
nCounter = nCounter + 1 //increments the counter by one
end
nAvg = nTotal / nCounter //calculates the average
display “The average marks of the class is”
display nAvg //displays the average
end
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The repeat…until Loop
:
:
repeat
begin
:
:
end until (condition)
:
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The goto Statement


A goto statement is used in situations in which the execution of a
pseudocode does not follow the steps in a sequential order.
To use a goto statement in a pseudocode, you need to use labels. A
label identifies the position in a pseudocode where the control of
execution can reach using a goto statement. While assigning name
to a label, a colon should follow the label name.
begin
numeric nCounter
nCounter=2
Label1:
nCounter=nCounter+2
display nCounter //displays all the even numbers
if(nCounter<=100)
goto Label1 //transfers the control to Label1
end
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Modular Approach to Programming
A program needs to be amended periodically to
respond to changing conditions or requirements.
This encouraged programmers to adopt a more
disciplined approach to program writing.
The techniques that were adopted are known as
structured programming techniques.
Structured programming includes features that are
designed not only to solve the problem at hand but
also to make the logic clear to someone reading the
program.
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Modular Approach to Programming
Long, continuous programs can be broken up into a series of individual
modules that are related to each other in a specified manner.
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Procedure
Procedure:
In a modular approach, one of the methods of representing a module is
procedure.
The working of a procedure is termed as a call-return mechanism .
The following steps are part of a call–return mechanism:
A procedure is called.
The set of operations stored within the procedure are executed.
The control is returned to the calling code.
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Procedure
Declaring, Defining, and Invoking Procedures:
Procedures need to be declared and defined before they can be called. The
declaration of procedures is similar to a declaration of any other variable in
an pseudocode.
Procedures are declared using the following syntax:
procedure <procedure_name>
The procedure is defined when the procedure is expressed with its body. The
syntax of the procedure definition is:
procedure <procedure_name>
begin //the set of statements of a procedure
end
The calling of a procedure is also called invoking a procedure. The method
for invoking procedure is known as a procedure call. The syntax of a
procedure call is:
call <procedure_name>
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Procedure
Problem Statement 1:
Accept the test scores for ten students and display their individual averages. The
scores of the students cannot be negative.
The following table lists the variables used in the solution.
NIIT
Variable
Data Type
Variable Name
Student Name
character
cStudentName
Score of Test1
numeric
nTest1
Score of Test2
numeric
nTest2
Score of Test3
numeric
nTest3
Average of Test Scores
numeric
nAverage
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Procedure
Solution:
//code segment to calculate average marks of 10
students
procedure Accept // declaring subprogram Accept
procedure Average // declaring subprogram Average
begin
numeric nTest1, nTest2, nTest3, nAverage
character cStudentName
call Accept
// calling subprogram Accept
call Average
// calling subprogram Avearge
display cStudentName nAverage
end
// code for the subprograms comes here
:
:
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Procedure
Accept
Accept cStudentName
Accept
Average
Accept nTest1
Average
nAverage=(nTest1+nTest2
+nTest3) / 3
Accept nTest2
Display cStudentName,
nAverage
Return
Accept nTest3
Is
nTest1>=0 AND
nTest2>=0 AND
nTest3>=0 ?
Yes
No
Return
Display “Test score cannot
be less than zero”
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Procedure
Problem Statement 2:
The total expenditure on salaries for the month needs to be calculated. As per
company policy an employee receives a minimum of $500. Depict the logic for
automating the task by using pseudocode and flowchart.
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Solution
Solution:
:
if
cChoice = “ Y”
begin
call Accept
call Summation
end
//invoking Accept
//invoking Summation
:
:
procedure Accept //statements of the subprogram
:
begin
accept nSalary
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Solution
if nSalary >=500
begin
return // returning the value
end
else
begin
display ‘Salary cannot be less than $500”
end
endif
end
// end of the subprogram
procedure Summation // statements of the subprogram
begin
nTotSalary = nTotSalary +nSalary
return nTotSalary
end
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Procedure Parameters
Procedure Parameters:
Parameters are like a bridge between the procedure and the
calling code.
Parameters comprise data that is used and processed by a
procedure.
Parameters can be variables of the numeric or character
data type.
Parameters are used to perform the following tasks:
Send data to a procedure
Retrieve data from a procedure
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Function
Function:
A function is a block of statements that perform a specific task. The underlying
fundamental of functions and procedures are very similar, and they can be used
interchangeably.
The difference between a function and a procedure is that a procedure does not return
any value to a calling program while a function returns a value to the calling program
after it is executed.
The functions in a pseudocode interact with each other by passing and receiving data.
Functions also operate on the call–return mechanism. The following are the steps in the
call–return mechanism using functions:
The function is called from the calling code.
The sets of operations within the functions are executed.
The execution is returned to the calling code using a return value
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Function
Declaring, Defining, and Invoking Functions:
Functions are declared like any other procedure or variable. The declaration
format is function <function_name>
The function are defined same as procedures. The only difference is that they
have a return statement at the end. The syntax of the function definition is:
function <function_name>
begin
//the function statements
return // The function returns some value
end
After a function is declared, it can be invoked from the pseudocode. The
method for invoking functions is known as a function call. The syntax for the
function call is:
call <function_name>
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Function Parameters
Function Parameters:
Function parameters form an interface between the function and the
calling code.
Functions accept values in the form of parameters. If parameters are
specified, they should be separated using commas.
Unlike procedures, the functions use the parameters only for receiving
data from the calling code.
They send value to the calling code using the return statement.
Therefore, functions have only input parameters.
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Scope of Variables
Scope of Variables:
Variables can be declared within or outside the begin…end block of a main
pseudocode, procedure, or function.
Depending on the place where variables are declared the variables have two
types of scope.
Local Scope
Global Scope
The variables that are declared inside the begin...end block of a main
pseudocode, function, or procedure have local scope and they are called
local variables.
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Scope of Variables

The following pseudocode describes the local scope of the variables.
begin
numeric nNum
display “Enter any number”
accept nNum
if (nNum > 10)
begin
numeric nRemainder
nRemainder = nNum % 2
display nRemainder
end
endif
end
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Scope of Variables
Following pseudocode describes the local scope using function.
begin
numeric nNum
display “Enter any number”
accept nNum
if (nNum > 10)
begin
call displayRemainder(nNum)
display nRemainder //an invalid statement
end
endif
end
function displayRemainder (numeric nNumber)
begin
numeric nRemainder
nRemainder = nNumber % 2
display nRemainder
end
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Scope of Variables
Procedure Test()
begin
numeric nX, nY
nX = 6
nY = 10
Display nX, nY
Call Test ()
End
Procedure Test()
Begin
numeric nX
nx = 9
Display nX, nY
End
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Scope of Parameters
Scope of Parameters:
The parameters of a procedure or function are variables that can be
accessed only from inside the procedure or the function.
This implies that the parameters act as the local variables of a function or
a procedure.
The following comprise the scope of parameters:
Parameters exist only inside the function or procedure for which they are defined. They
cannot be accessed from outside the function or procedure.
They retain their value until the function or procedure is executed.
Parameters are initialized every time the function or procedure is called.
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Questions

A compiler is:




A detailed flowchart is called a:
A high-level language
Language-specific
A machine language
A source code




The symbol that represents
comments in a flowchart is:




A procedure/subroutine symbol
An input symbol
An annotation symbol
A flow line
NIIT
Macro flowchart
Lengthy flowchart
Micro flowchart
Detailed flowchart
Which of the following is NOT a
type of algorithm?




Flowchart
Program
Pseudocode
Decision table
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Question
Literals are:

Values that change continuously

Memory locations

Values that do not change

Names given to variables
Which operators are used to test the
relationship between two variables or
between a variable and a constant?




A statement consisting of
variables, literals, constants, and
operators is called a/an:

Function
 Identifier

Operator

Expression
NIIT
Arithmetic operators
Logical operators
Relational operators
Special operators
Input is accepted using the keyword
accept in:

Pseudocode

A Flowchart
 An Algorithm

An Expressiont
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THANK YOU
Any questions?