无法在java中获取Switch案例的行为 [英] Unable to get behaviour of Switch case in java

问题描述

我在java 6中编写了小代码

I have written small code in java 6

public class TestSwitch{

public static void main(String... args){
    int a = 1;
    System.out.println("start");
    switch(a){
        case 1:{
            System.out.println(1);
            case 3:
                System.out.println(3);
            case 4:
                System.out.println(4);
        }
        case 2:{
            System.out.println(2);
            case 5:
                System.out.println(5);
            case 7:
                System.out.println(7);
        }

    }
    System.out.println("end");
}
}

输出：开始1 2结束

我的编辑器显示案例3的孤立案例和'案例5'。它仍然运行
并显示输出。

My editor is showing orphaned case for 'case 3' and 'case 5'.Still it is running and showing output.

• 在Java中是否存在类似概念的Nastated案例？



• 为什么要提供以上输出？相反，我认为这将是'开始1结束'

• Does Nastated cases like concept is there in Java?

• And Why it is giving above output? rather i thought it will be 'start 1 end'

您的回复将不胜感激!!

Your response will be greatly appreciated!!

推荐答案

切换替换if else但切换语法！= If else语法。

在每个案例之后你忘记了 break 。

You forgot to put break after each case.

因此下的条件下降通过。

示例：

case 0:
          mColor.setText("#000000");
          break;

你可以在文档中找到

中断语句是必要的，因为如果没有它们，switch块中的语句将会失败：匹配的case标签之后的所有语句将按顺序执行，而不管后续case标签的表达式如何，直到遇到break语句。

The break statements are necessary because without them, statements in switch blocks fall through: All statements after the matching case label are executed in sequence, regardless of the expression of subsequent case labels, until a break statement is encountered.

public static void main(String... args){
        int a = 1;
        System.out.println("start");
        switch(a){
            case 1: 
                System.out.println(1);
                break;
            case 2:
                  System.out.println(2);
                  break;
            case 3:
                System.out.println(3);
                break;
            case 4:
                System.out.println(4);
                break;
            case 5:
                System.out.println(5);
                break;
            case 7:
                System.out.println(7);
                break;
            default:
                System.out.println("nothing");

            }

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