While loop

A while loop is used to execute a piece of code while a condition is true. The while loop is to be used when a block of code is to be executed a variable number of times. For example the code shown gets the user input, as long as the user inserts numbers which are not 0. If the user inserts 0, the while condition is not true anymore so execution will exit the loop and continue on to any subsequent code:

int num = 1;

while (num != 0)
{
    scanf("%d", &num);
}