java循环语句（国外英文资料）.docVIP

java循环语句（国外英文资料） The Java looping statement has for, while, and do-while. These statements create what we usually call loops. You may know that a cycle repeats the same set of instructions until an end condition appears. As you will see, Java has a loop structure that is suitable for any programming. 5.2.1 while statements The while statement is the most basic loop in Java. When its control expression is true, the while statement repeats a statement or statement block. Its general format is as follows: While (condition) { / / the body of the loop } Condition condition can be any Boolean expression. As long as the conditional expression is true, the loop body is executed. When condition condition is false, program control is passed to the statement line following the loop. Curly braces are not necessary if only a single statement needs to be repeated. The while loop below starts the subtracting count from 10 and prints 10 tick lines. / / Demonstrate the while loop. The class While { Public static void main (String args []) Int n = 10; While (n 0) ( tick + n); N --; } } } When you run this program, it tick 10 times: Tick ten Tick 9 Tick eight Tick 7 Tick 6 Tick 5 Tick 4 Tick 3 Tick 2 Tick 1 Because the while statement computes the conditional expression at the beginning of the loop, if the condition is false at first, the loop will not execute once. For example, in the following program, the call to println () has never been executed: Int a = 10, b = 20; While (a b) A. out.println ( This will not be displayed ); The while loop (or any other loop in Java) can be empty. This is because a null statement (a statement consisting only of a semicolon) is legal in Java syntax. For example, the following program: / / The target of a loop can be empty. The class NoBody { Public static void main (String args []) Int I, j; I = 100; J = 200; / / find midpoint between I and j While (+ + I - j); / / no body in this loop (1) the Midpoint is Midpoint is. } } The program finds the m