What is the difference between do while and while in C language?

Answer 1

While

Do-While

1. In this statement, the Boolean expression is checked before executing the loop body.

1. In this statement, the Boolean expression is checked after executing the loop body for the first time.

2. It doesn't execute its statement if the condition fails.

2. It will execute its statements at least once even if the condition fails. After that if the condition founds false the execution stops.

It is mainly used in menu like programs where all the available choices are printed at least once.

3. General loop form is

while (condition)

{

statements

}

3. General loop form is

do

{

statements

} while (condition)

4. Executing a code at least once tend to be relatively rare, thus the simple while is more commonly used

4. This used for a block of code that must be executed at least once

5. While loop is entry control loop

5. Do while is exit control loop