while loop in C

While loop is also known as a pre-tested loop. In general, a while loop allows a part of the code to be executed multiple times depending upon a given boolean condition. It can be viewed as a repeating if statement. The while loop is mostly used in the case where the number of iterations is not known in advance.

Syntax of while loop in C language

The syntax of while loop in c language is given below:

Flowchart of while loop in C

Example of the while loop in C language

Let’s see the simple program of while loop that prints table of 1.

Output

1 2 3 4 5 6 7 8 9 10 

Program to print table for the given number using while loop in C

Output

Enter a number: 50 50 100 150 200 250 300 350 400 450 500 

Enter a number: 100 100 200 300 400 500 600 700 800 900 1000 

Properties of while loop

• A conditional expression is used to check the condition. The statements defined inside the while loop will repeatedly execute until the given condition fails.
• The condition will be true if it returns 0. The condition will be false if it returns any non-zero number.
• In while loop, the condition expression is compulsory.
• Running a while loop without a body is possible.
• We can have more than one conditional expression in while loop.
• If the loop body contains only one statement, then the braces are optional.

Example 1

Output

3 5 7 9 11 

Example 2

Output

compile time error: while loop can't be empty 

Example 3

Output

infinite loop  

Infinitive while loop in C

If the expression passed in while loop results in any non-zero value then the loop will run the infinite number of times.