COMPUTER PROGRAMMING
COURSE 66111
DR. EMAD NATSHEH
Adapted from the slides originally prepared by
Dr. Luai Malhis, Eng. Muhannad Al-Jabi, Eng. Haya Samma’aneh, &
Dr. Samer Arandi
Part 1
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Introduction
Numbering Systems
First C++ Program
What is the computer?

The computer is a programmable machine that
receives input, manipulates and stores data, and
produces output in a useful format.
How does the computer work?
The computer works as a result of the interaction of
two categories of components:

Software Components: programs which contain
Instructions that command the computer to perform
actions.

Hardware components: Physical components of the
computer.
Computer Organization (Hardware)

Most computers have six basic components:
 Input
devices
 Output devices
 Memory unit
 Arithmetic Logic Unit
 Control Unit
 Secondary storage unit
Computer Organization (Cont.)

Input unit:

Obtains information from input devices


Keyboard, mouse, microphone, scanner, networks, etc
Output unit

Places information processed by computer on output devices

Screen, printer, etc.
Computer Organization (Cont.)

Memory unit (Primary)

Internal data storage in a computer





An ordered sequence of storage cells
Each memory cell has a distinct location
Rapid access, relatively low capacity
Holds data (input data or the product of computation), and instructions
(programs)
Secondary Storage





Slower to access than primary memory
High-capacity (warehouse) section
Stores inactive programs or data
Less expensive per unit than primary memory
Secondary storage devices

Hard drives, CDs, DVDs
Computer Organization (Cont.)

Central processing unit (CPU)


Part of computer that executes instructions
Consists of:

Arithmetic and Logical Unit (ALU)



Performs arithmetic calculations (addition, subtraction, etc) and logic
decisions (determining if a number is greater, less, or equal to other number,
etc)
Control Unit (CU): manages the action of the other components so
that program instructions execute in the correct order.
A set of registers

The CPU has its own small
workspace, consisting of
several registers, each of
which can hold a number.
More on the CPU

The CPU fetches the program instructions from memory and executes them.
The memory also holds the input/output data of the program.

A specific register holds the memory address of the program instructions. The
CPU uses this address to fetch the program instructions for execution,
consecutively.

A group of registers holds the input and output data values (operands) during
the execution of the instruction by the ALU

Input operands are typically fetched from memory before execution and
stored back to memory after execution
Computer Software


Software: programs that enable the hardware to
perform different tasks
Types of software:
 System
software: essential for computer operation and
support (e.g. operating systems: Windows, Linux, Mac)

Application software
 Tools
used to accomplish specific tasks. (e.g. image
viewers, word processors, games, scientific applications, etc)
Programming languages


Machine language (Low Level Language):The language that
the computer directly understand. Generally consists of 0s and
1s. Almost impossible to understand by humans.
Assembly language (Low-level Language): cannot be
understood by the computer, it must be converted to machine
language by translator programs called assemblers
Programming languages

High level languages: C++, Java, C#, FORTRAN, etc.
 Similar
to everyday English.
 Uses common mathematical notations.
 Single statements to do multiple tasks
 Converted to machine language by translator
programs also called Compilers
 Example
code of high level language.
z=a+b
Bits and Bytes: Data representation


Bit (binary digit): is the basic unit of information in
computing. It is the smallest unit of storage that can
be either 0 or 1
Byte : 8 bits.
Amount of data
Numbering systems

Decimal --10 symbols (0,1,2,3,4,5,6,7,8,9)

Binary --2 symbols (0,1)

Octal --8 symbols (0,1,2,3,4,5,6,7)

Hexadecimal --16 symbols
(0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F)
A
= 10 , B = 11 ….F = 15
Decimal numbering system


Decimal numbers are made of decimal digits:
(0,1,2,3,4,5,6,7,8,9)
But how many items does a decimal (base 10) number
represent?
115 = 1x102 + 1x101 + 5x100

What about fractions?
97654.35 = 9x104 + 7x103 + 6x102 + 5x101 + 4x100 +
3x10-1 + 5x10-2
 In formal notation  (97654.35)10

Binary numbering system


Binary numbering system, or base-2 number
system, represents numeric values using two
symbols, 0 and 1.
Binary system is used internally to represent data
by all computers.
Converting from binary to decimal

Convert (11001)2 to the decimal system
 (11001)2=
1x24+1x23+ 0x22 + 0x21 +1x20
= 16 + 8 + 0+ 0 +1
= (25)10
The sum of the last row = (25)10
Converting from decimal to binary




Divide the decimal number
by 2.
Put the division result in the
next row under the number.
Put the division remainder
next to the number in the
same row.
Repeat the 3 steps for the
division result until the
division result is zero.
Octal numbering System



Octal numbers are made of octal digits:
(0,1,2,3,4,5,6,7)
Octal numbers don’t use digits 8 or 9
Note that each octal digit can be represented
with three bits.
Converting from octal to decimal

Convert (357)8 to the decimal system
 (357)8 =
3x82 + 5x81 +7x80
= 192 + 40 +7
= (239)10
The sum of the last row = (239)10
Converting from decimal to octal




Divide the decimal number by 8.
Put the division result in the next
row under the number.
Put the division remainder next
to the number in the same row.
Repeat the 3 steps for the
division result until the division
result is zero.
(239)10 = (357)8
Converting from octal to binary


Each digit in the octal
number is represented
by 3 digits in binary.
Example :
(63)8 = (110011)2
Converting from binary to octal


Start from right to left, create groups of digits,
such that, each group contains three digits only.
If the last group contains less than 3 digits, add
zeros to the left.

Write down the equivalent symbol for each group.

Example : (010 101 110)2 =(256)8
Hexadecimal numbering system

Each digit in hexadecimal number contains one of
the following symbols:
(0,1,2,3,4,5,6,7,8,9,A, B, C, D, E, F)

Note that each hexadecimal digit can be
represented with four bits.
(1110) 2 = (E)16
Converting from hexadecimal to
decimal

Convert (3A9F)16 to the decimal system
 (3A9F)16=
3x163 + 10x162 +9x161 +15x160
= 12288 + 2560+144+15
= (15007)10
The sum of the last raw = (15007)10
Converting from decimal to
hexadecimal




Divide the decimal number by 16.
Put the division result in the next
row under the number.
Put the division remainder next to
the number in the same row
represented in hexadecimal.
Repeat the 3 steps for the division
result until the division result is zero.
(171)10 = (AB)16
Converting from hexadecimal to binary


Each digit in the
hexadecimal number
is represented by 4
digits in binary.
Example :
(63)16= (01100011)2
Converting from binary to hexadecimal




Start from right to left, create groups of digits, such that, each group
contains four digits only.
If the last group contains les than 4 digits, add zeros to the left.
Write down the equivalent symbol for each group (you can use the
table on the previous slide)
Example : (000101011101)2=(15D)16
Converting between octal and
hexadecimal

There is no direct way to convert between the two
systems. So we can either:
 Convert
the number to decimal then to the desired
system
 Convert the number to binary then to the desired
system

The second method is much easier because it avoids
the mathematical operations needed by the first
method.
What do we mean by a program?

It is a set of ordered instructions that performs a
certain task.
Instruction A is executed before instruction
B, as long as instruction A is located before
instruction B.

For example, some instructions of your daily
program:Wake up
Dressing
Go to school
Stages of program development
Program execution and testing
Program loading
Program linking
Program compilation
Program writing
Program design
Problem statement
Problem Statement


What is the problem? Why the program is needed?
What is the scope and limitations (in time, and
accuracy) that can be used to solve the problem?
Program Design


Find a suitable algorithm to solve the problem.
One way to represent the algorithm is by drawing a
Flowchart of that algorithm.
What does it mean?
Flowchart example 1
C/C++ Programming Language

History of C
 Evolved from two other programming languages
 BCPL and B
“Typeless” languages
Dennis Ritchie (Bell Laboratories)


 Added





data types and other features
Hardware independent
 Portable programs
1989: ANSI standard
The C Language was extended to contain classes and other
Object Oriented features and named as C++.
Many Other Languages currently developed uses syntax and
symantics similar to C.
C/C++ is traditionally the first language a programmer
learns.
Program writing


When you write a C++ program you store what you
write in a text file called a source code file or simply a
source file.
The name of the file ends in .cpp


(example: program.cpp)
The part of the name before the period is called the
base name, and the part after the period is called the
extension.
Program writing

We will use Microsoft Visual Studio 6.0.

It can be used for :
 Program
writing
 Program compilation & linking
 Program execution and testing.
How to start writing a program?

After installing Microsoft Visual Studio C++ 6.0

Go to all programs menu from desktop.

Select Microsoft Visual Studio 6.0.

Select Microsoft Visual C++ 6.0
How to start writing a program?

From file menu select new.

Select the projects tab.

Select the win32 console application

Select Empty Project
How to start writing a program?
How to start writing a program?

From the file menu select new.

Select the file tab.

Select the C++ source file option.
How to start writing a program?
Example #1
Write a C++ program that prints hello on the
screen.
Example #1 … Hello World
Compile a C++ program


To compile a C++ program, press ctrl+F7
If there are no errors, press ctrl+F5 to run the
program.
How to find compilation errors




In the window below the source code editing page.
Find the error(s) using the right slide bar
When you double click on an error, a notification arrow will
point to the source code line that contains the error.
Solve the first error first, then the second and so on.
Programming errors

Syntax errors: violation of the syntax ( grammar rules ) of the
programming language




Run-time errors: errors detected when the program is run



errors that prevent your program from running
The compiler gives an error message if the program contains a syntax error
Most compiler errors are caused by mistakes that you make when typing code.
For example, you might misspell a keyword, leave out some necessary
punctuation, or try to use an End If statement without first using an If statement.
The system usually gives an error message during execution
An example of this is division by zero
Logic errors: program compiles and runs normally, but does not perform
properly. Caused by an error in the logic of the program
Comments





Important part of the program
Non-executable (not compiled) statements
Describe the purpose of the program or parts of the program
Indicated by:
 the double slash
 // everything to the right of the double slash until the end of
the line is ignored
 the slash asterisk combination
 /* everything between the enclosing and ending symbols is
ignored, typically used for comments spanning multiple lines
*/
Provide documentation
More Special Characters