For Loop and While Loop in Pascal Programming – Lesson 7

Last updated on October 8th, 2023 at 03:14 pm

In this article, we seek to explore the for loop and while loop in Pascal programming. Loops make our lives easier. They are great tools in programming when we have large amounts of repetitive processes to run.

In this article, we will explore:

• Examples of how to set up and use the for and while loops;
• Writing the for and while loops in both algorithms and Pascal programming; and
• A trace table of the looping structure.

What are the for and while loops used for?

In Pascal programming, the for and while loops allow us to reduce thousands of lines of code in order to perform repetitive tasks. In programming, a loop repeatedly processes pieces of code until some condition is no longer true.

Example 1 – Loops

Write a program that accepts the names of three students as input, number and print each child’s name.

The problem defining diagram

Input	Process	Output
childName	1. Get the childName	Count
	2. Set the number	childName
	3. Print the childName and number.

Pseudocode and flowchart of the loop above

Test data – Names

1. Sue Ann
2. Misty
3. Arlene

Trace table of the loop in example 1

Step	count	count<=3	childName	Output
1	1
2		true
2 a				What is your child’s name?
2 b			Sue Ann
3				1
4				Sue Ann
5	2
2		true
2 a				What is your child’s name?
2 b			Misty
3				2
4				Misty
5	3
2		true
2 a				What is your child’s name?
2 b			Arlene
3				3
4				Arlene
5	4
2		False

Example of the Pascal program using the while loop

program childrenName;

var
count : integer;

childName : string;

begin
count := 1;

while(count<=3)do

    begin

    writeln('Please enter the name of your child:');

    readln(childName);

    write(count,'.');  
    writeln(childName); 
    count := count + 1;

end;

end.

Loops are often used with control structures and arrays to make our work easier. If you wish to explore control structures, be sure to explore our articles on case statements.

Example 2 – Loop

Write a program that takes in several employees’ names and years of service. The program should check their years of service and print the names of all the employees with more than 5 years of service.

The problem defining diagram of example 2

Input	Process	Output
names	1. Read names.	names
yearsOfService	2. Read the yearsOfService.
	3. Find the names of all the persons who have served for more than 5 years.
	4. Print names

The Pseudocode and flowchart of the for loop example 2

Test data

Names	YearsofService
Aalyah Bowen	5
Louis Smith	6
Jason Lance	2

Trace table of the for loop example 2

Steps	count	Names	YearsOfService	YearsOfService >5	Output
1	1
1 a					Please enter the names of your employees.
1 b		Aalyah Bowen
1 c					Please enter the years of service.
1 d			5
1 e				false
1	2
1 a					Please enter the names of your employees.
1 b		Louis Smith
1 c					Please enter the years of service.
1 d			6
1 e				true
1 e i					Louis Smith
1	3
1 a					Please enter the names of your employees.
1 b		Jason Lance
1 c					Please enter the years of service.
1 d			2
1 e				false

Pascal program of the for loop – example 2

program yearsServed;

var
names : string;
yearsOfService : integer;
count : integer;

begin
for count := 1 to 3 do
begin
    writeln('Please enter the names of the employees:');
    readln(names);
    writeln('Please enter the years of service of this employee:');
    readln(yearsOfService);
    if(yearsOfService>3)then
    begin
        writeln(names);
    end;
end;
end.

If you are interested in learning more about the for and while loops, you should explore our article on arrays.

Before you go

We have multiple articles exploring programming in Pascal, which you should explore to become a better Pascal programmer. Be sure to check them out.

We try our best to be as thorough as possible in the information we provide. However, if you have any questions or comments, be sure to leave them in the comment section below, and we will get back to you.