King Saud University
College Of Applied Studies and Community Services
CSC 1101
Computer Programming-1
Done By: Asmal Alosaimi
Edited By: Noor Alhareqi & Alaa Altheneyan
CHAPTER 1
PSEUDOCODE & FLOWCHARTS
1st Semester 1433-1434 H
Levels of Program Development
2
1.
2.
3.
4.
5.
6.
Define the problem. Human thought
Plan the problem solution. writing the
algorithm [pseudo-natural language (English,
Arabic) or drawing the flowchart diagram).
Code the program. High Level
Programming Language (C, C++, Java, …)
Compile the program. Machine Code
Run the program.
Test and debug the program.
Asma Alosaimi
From Lec1 we learn that
3
When planning for a problem solution, algorithms are
used to outline the solution steps using
English like statements, called pseudocode.
or
A flowchart , which is a graphical representation of
an algorithm.
Asma Alosaimi
Pseudocode
4
Pseudocode is a detailed description of what a
computer program must do, expressed in an English
like language rather than in a programming
language.
Asma Alosaimi
Pseudocode Example
5
1.
2.
3.
4.
5.
6.
Write a Program to Print the Sum of two integer
Numbers
Start the program
Read the first number and save in the variable ( N1 )
Read the second number and save in the variable (
N2 )
Sum the both numbers and save the result in the
variable ( Sum ) Sum = N1 + N2
Print the variable ( Sum )
End the program
Asma Alosaimi
Flowchart
6
A flowchart is a type of diagram that represents
an algorithm , showing the steps as boxes of various
kinds [ex: rectangles, diamonds, ovals], and their
order by connecting these with arrows.
Asma Alosaimi
Flowcharts Symbols
7
Start
Start/End
Read n1
Read/Print
End
Print n1
N2 = n1+3
n1 > 3
N2 = 5
Arithmetic Operations
Decision , can be used with loops
Solution
8
start
Draw a flowchart for a program that calculates
Read L, W
and print the area and the perimeter of
a rectangle.
area = L * W
Input
Length
width
perimeter = 2 (L+W)
Processing
Area = length*width
Print area
Perimeter = 2*( length + width)
Print perimeter
Output
Area
Asma Alosaimi
End
Perimeter
Example 2
9
Draw the flow chart for a program that calculates
the total salary for an employee using this equation:
Total_Sal = Salary +Overtime
Asma Alosaimi
Solution
10
Input
Salary
Overtime
Processing
Total_Sal = Salary +Overtime
Output
Total_Sal
start
Read Salary
Read Overtime
Total_Sal =
Salary +Overtime
Print Total_Sal
Asma Alosaimi
End
Example 3
11
Draw a flowchart for a program that calculates and
prints the sum of the even integers from 2 to 30.
Input
No input.
Processing
Sum = 2+4+6+8+……+28+30.
Output
sum
Asma Alosaimi
Solution
12
Pesudocode:
Start the program
Create a variable to hold a counter from 2 to 30.
Initialize the counter to 2.
Create a variable to hold the sum.
Initialize the sum to zero.
Loop While the counter is less-than-or-equal to 30
add the counter to the sum
add two to the counter.
repeat until the counter reach 30
Print the sum.
End of program
Asma Alosaimi
Solution
13
Start
Counter=2, Sum=0
no
yes
Counter≤30
yes
Sum= Sum + Counter
Counter=Counter+2
Print Sum
Asma Alosaimi
End
Example 4
14
Draw a flowchart for a program that determine if
the temperature degree is above or below freezing.
Input
Temp.
Processing
Check if Temp is below the 32 below freezing.
Check if Temp is above the 32 above freezing.
Output
Print “below freezing” or “above freezing”
Asma Alosaimi
Solution
15
Asma Alosaimi
Example 5
16
Draw a flowchart for a program that accepts a
person’s initial bank balance followed by a
sequence of numbers representing transactions. A
positive number represents a credit entry in the
account and a negative number represents a debit
entry. The input is terminated by a zero entry. The
program should print the new balance.
Asma Alosaimi
Solution
17
Input
bank balance.
transactions
Processing
balance = balance + transaction.
Output
balance
Asma Alosaimi
Solution
18
Start
Read balance
Read transaction
balance =balance + transaction
Transaction !=0
yes
no
Print balance
Asma Alosaimi
End
Example 6
19
Draw a flowchart for a program that calculates the
Zakat, where the user enter the amount of money
then the program show the zakat.
Zakat
Zakat
=(2.5/100) * amount.
is not calculated if the amount is less than 1000
S.R
Asma Alosaimi
Solution
20
Input
amount.
Processing
Check if amount is below 1000 Zakat =0.
Check if amount is above 1000 Zakat =(2.5/100) *
amount
Output
Zakat
Asma Alosaimi
Solution
21
Start
Read amount
no
yes
Amount > 1000
Zakat =0.
Zakat =(2.5/100)*amount
Print Zakat
Asma Alosaimi
End
0
