While Loop vs. Do-While Loop – Comparison & Differences

Loops are vital programming components that help to write identical sequences repeatedly. While Loop and D0-While Loop are the essential types of loops that aid in making programming easy.

Main Difference

While Loop enables consumers to execute a part of code multiple times depending upon the need of Boolean condition. On the flip side, in Do-While Loop, the controlling constraint appears at the end of the Loop.

The use of these loops relies on the necessity of consumers. While Loop plays its role in uncertain situations, Do-While Loop is just a variant of a While Loop. Let us discuss the significant differences between them.

What is a While Loop?

While Loop repeats one code repeatedly until or unless a specific condition is actual, the situation is checked at the beginning of each iteration, and the code block is executed if it proves true. This Loop is mainly used where the consumer does not know how often he has to repeat the process. So, he relies on While Loop to make programming easy and efficient.


  • Repetition of the same procedure
  • Execution of target statement
  • Pre-test loop
  • Reliable
  • Entry control loop

What is Do-While Loop?

Do-While Loop is a variant of While Loop in which a minimum of one statement is executed. Do-While Loop is also known as exit-controlled Loop because iteration occurs at least once even though the condition is false at the first iteration. There is always a semicolon after each situation in the syntax. In Do-While Loop, the variable may be initialized before or within the Loop.


  • Checking of condition at the end of Loop
  • Variant of While Loop
  • Easy to understand
  • Exit controlled Loop

Key Differences between While Loop and Do-While Loop

  1. The While Loop controlling condition appears at the start, while the Do-While Loop controlling condition occurs at the end.
  2. While Loop is an entry-controlled loop, Do-While Loop is an exit-controlled loop.
  3. While Loop is a pre-test loop, Do-While Loop is a post-test loop.
  4. While Loop iteration does not occur if false at the first iteration, in Do-While Loop, one iteration is a must, even if the condition is wrong at the first iteration.
  5. In While Loop, there is no semicolon, whereas in Do-While Loop, there is a semicolon at the end.
  6. Comparison table of  While Loop vs. Do-While Loop
Feature While Loop Do-While Loop
The appearance of controlling condition At the first At the end
Loop type Entry controlled Exit controlled
Testing type Pre-test Post-test
Semi Colon No Yes


In a nutshell, we can say that While Loop and Do-While Loop are pretty different. They are different in features and functions; however, the While Loop is a pre-test loop, while Do-While Loop is a post-test loop.