java控制语句 if-else while do-while for return break continue goto switch default

if

for

//: object/ForEachFloat.java
package object;
import java.util.Random;
public class ForEachFloat
{
    public static void main(String[] args)
    {
        Random rand = new Random();//47是随机种子,如果不提供种子,默认为系统时间
        float f[] = new float[10];
        for(int i = 0; i < 10; i++)
            f[i] =     rand.nextFloat(); //生成0-1之间的float值
        System.out.println('\n');
        for(float x : f)  //将f数组的值按顺序赋予x
            System.out.printf("%f\t",x);
    }
}
 

 break continue goto

java 没有goto,可以用标签 和 break;continue 配合完成goto 的功能

//: object/LabeledFor.java

package object;

import static net.mindview.util.Print.*;

public class LabeledFor{
    public static void main(String[] args)
    {
        int i = 0;
        outer: //Can't have statements here
        for(;true;){//infinite loop  无限循环
            inner: //Can't have statements here
            for(;i<10;i++){
                print("i = " + i);
                if(i == 2){
                    print("continue");
                    continue;
                    }
                if(i == 3){
                    print("break");
                    i++; //otherwise i never
                         // gets incremented
                    break;
                }
                if(i == 7){
                    print("continue outer ");
                    i++; //otherwise i never
                         // gets incremented
                    continue outer;//回到outer标记重新循环
                }
                if(i == 8){
                    print("break outer");
                    break outer;  //跳出outer 标记的循环语句
                }
                for(int k = 0;k<5;k++){
                    if(k == 3){
                        printf("contniue inner ");
                        continue inner;
                    }
                }
            }
        }
    }
}