The next program provides another example of the use of the while statement. The program computes the greatest common divisor of two integer values. The greatest common divisor (we abbreviate it hereafter as gcd) of two integers is the largest integer value that evenly divides the
two integers. For example, the gcd of 10 and 15 is 5 because 5 is the largest integer that evenly divides both 10 and 15.