格式:
while(判断条件语句){
循环体语句;
}
扩展格式:
初始化语句;
while(判断条件语句){
循环体语句;
控制条件语句;
}
实例一
猜字游戏
思路:
While循环:
猜的数字:int num = 456;条件:int guess;while(guess != num){猜数字;guess < num;猜小了guess > num;猜大了guess == num;break;}猜对了! public class WhileDemo {public static void main(String[] args) {//int num = 456;//随机产生 Math.random()------0.0-0.9999999...int num = (int)(Math.random()*1000) + 1;//System.out.println("要猜的数字是" + num);Scanner sc = new Scanner(System.in);System.out.println("请输入猜的数字:");int guess = sc.nextInt();while(guess != num){if(guess > num){System.out.println("猜大了");}else{System.out.println("猜小了");}System.out.println("继续猜!");guess = sc.nextInt();}if(guess == num){System.out.println("恭喜你,猜对了");}sc.close();}} do-while循环语句格式:
do{
循环体语句;
}while(判断条件语句);
实例一
猜字游戏
public class DoWhileDemo {public static void main(String[] args) {int num = (int)(Math.random()*1000) + 1;Scanner sc = new Scanner(System.in);System.out.println("请输入要猜的数字");int guess = sc.nextInt();do{if(guess > num){System.out.println("猜大了");}else{System.out.println("猜小了");}System.out.println("继续猜!");guess = sc.nextInt();}while(guess != num);if(guess == num){System.out.println("猜对了");}}} break和continue的区别:continue:使用循环结构中,用于结束本次循环继续下一次循环。
break:可以使用在switch结构和循环结构中,用于跳出当前结构。
案例
public class Test {public static void main(String[] args) {for (int i = 0; i < 10; i++) {if(i % 2 == 0){continue;}System.out.print(i);}}} public class Test {public static void main(String[] args) {for (int i = 0; i < 10; i++) {if(i == 2){break;}System.out.print(i);}}}