Introduction:

The do$-$while loop was added to C$++$ to give us a slightly different way to execute a block of code repeatedly. As you may recall the syntax of the while loop is given by:

initialization statement

while $($ logical expression $)$

$\{$

block of code to be repeated

update variables in logical expression

$\}$

The do$-$while loop moves the logical expression after the block of code to be repeated. The do$-$while syntax is shown below:

initialization statement

do

$\{$

block of code to be repeated

update variables in logical expression

$\}$

while $($ logical expression $)$;

With a do$-$while loop, the block of code is executed before the logical expression is evaluated. If the logical expression is TRUE, the block of code is executed again, and the process repeats until the expression is FALSE. With a do$-$while it is possible to execute he block of code once even if the logical expression is false. As we will see, this program logic is useful for checking user input.