Flow Control 3: while, do-while

public class WhileLoopDemo {
        /* The Java Language provides the while and do-while
         * loops to allow code to execute repeatedly until a
         * condition is no longer true.
         *
         * The primary difference between while and do-while
         * is the point at which the expression is evaluated.
         *
         * For while loops the expression is evaluated at the
         * top of the loop. The beginning of the code block.
         * So if the expression evaluates to false. The
         * following statements will not run.
         *
         * do-while loops evaluate their expression at the bottom
         * of the loop. The end of the code block. So do-while
         * loops ALWAYS execute their statements at least once.
         */
        public static void main(String[] args) {
                int A = 0;
                int B = 5;

                /* The code in this while loop will only run
                 * because A is less than B.
                 */
                while(A < B) {
                        System.out.println("A = " + (A++));
                }

                // Now that A is = to B the code won't run any more.
                while(A < B) {
                        System.out.println("A = " + (A++));
                }

                /* But if we use a do-while loop. The code should run at
                 * least once.
                 */
                do {
                        System.out.println("\nThis is a do-while loop.");
                        System.out.println("A = " + (A++));
                } while (A < B);
        }
}