Difference Between While and Do While Loop
Although there exist various similarities between while and do while loops such as both are iterative statements, used to save effort and time of execution of a program but there exists a few difference between while and do while loops. These differences are important to know in order to use the apt loop statement as per our requirement. Now let us see the difference between while and do while loops in reference to the C and C++ languages.
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Key Difference Between While and Do While Loop
While Loop | Do While Loop |
The Keyword “while” is used. | The keyword “do while” is used. |
The control statement is executed before the loop body. | The control statement is present after the loop body. |
The loop body executes when the condition becomes true. | The loop body executes once, even if the condition is true or false. |
It follows a top-down approach. | It follows a bottom-up approach. |
For single statements, brackets are not required. | Brackets are always required. |
What is a While Loop?
As we have seen in the difference between While and Do While Loop. Let us see what is while loop in brief. It provides the mechanism to repeat a statement or block of statements if the condition turns out to be true. It runs until the condition becomes false; if the condition is never updated, then the while loop continues to execute infinite times, which is undesirable.
A while loop is also called a top-checking loop as the control condition is placed at the very first line of the code. If the control condition evaluates to false, then the statements enclosed in the loop are never executed.
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What is a Do While Loop?
It is similar to the while loop the only difference between while and do while loop is that in a do while loop, the test condition is tested at the end of the loop. This implies that the body of the loop is executed at least once without checking the condition.
The do while loop is a bottom-checking loop, as the control statement is placed after the body of the loop. Another difference between while and do-while loops is that the do-while loop executes at least one time.
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