The University of Babylon
Department of Software
LECTURE NOTES ON STRACTURE PROGRAMMING USING C++ LANGUAGE
By
Dr. Samaher Hussein Ali
College of Information Technology, University of Babylon, Iraq
Samaher_hussein@yahoo.com
3 December 2012
Algorithm and Flowchart
In the pervious lecture, we explained the algorithm as collection of steps require to solve problem and it must have the following conditions:(Keep it simple, Read the fascinating manual, Make your documentation short but sweet, Every subprogram should do something and hide something, Program defensively and Good program is a pretty program) In addition, there are three types of methods to write any algorithm, the methods include(set of instructions(i.e., Pseudo Code), Flowchart and Words)
Algorithm
Set of Instructions (pseudo code)
3 December 2012
Flowchart
Dr. Samaher Hussein Ali
Words
Notes of Lecture 2
Algorithm and Flowchart
Example: Write the algorithm to compute the result of the following mathematical
expression (R=a*b + c). Let: a and b are two variables from type integer while c is constant
(i.e., c=2.1).
Solution:
 Using the word method
1.
2.
3.
4.
5.
6.
7.

Start
Read the first number a
Read the second number b
Assignment value of the third number c
Compute the result (i.e., R=a* b +c)
Output R
End
Using the Flowchart method
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2
Algorithm and Flowchart
 Using the Pseudo Code (Set of Instructions) Method
/* This is the code to calculate the result of mathematical expression */
# include <iostream .h>
# include <conio.h>
int a;
int b;
float c;
float R;
void main( )
{
Cout<<“ Input the value of first number a:”<<endl;
Cin>>a;
Cout<<“ Input the value of second number b:”<<endl;
Cin>>b;
C=2.1;
Cout<<“ what is the result?”<<endl;
R=a*b + c;
Cout<<“Result=”<<R<<endl;
getch( );
}
3 December 2012
Samaher Hussein Ali
Notes of Lecture 2
Example 2: result1=(a*b+c ), result=(result1+2)/d
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2
Statements
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2
Comments
Comments are parts of the source code disregarded by the compiler. They simply do nothing. Their purpose is only to allow the programmer to insert notes or descriptions embedded within the source code.
C++ supports two ways to insert comments:
The first of them, known as line comment, discards everything from where the pair of slash signs (//) is found up to the end of that same line. The second one, known as block comment, discards everything between the /* characters and the first appearance of the */ characters, with the possibility of including more than one line.
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2
Variables
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2
Variable Types
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2
Variable Types
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2
Initialisation
3 December 2012
Dr. Samaher Hussein Ali
Notes of Lecture 2