带有错误输出的switch语句 [英] Switch statement with string wrong output

问题描述

我遇到了一个基本问题，即将开关大小写与字符串一起使用.

I came across this basic question, where switch case is used with string.

在案例之间不使用break语句，但是为什么即使不匹配case字符串也要在所有案例中使用它呢?

Break statement is not used between cases but why it going to all the cases even when it is not matching the case string?

所以我很好奇为什么输出3而不是1?

 public static void main(String [] args)
      {
        int wd=0;

        String days[]={"sun","mon","wed","sat"};

        for(String s:days)
        {
          switch (s)
          {
          case "sat":
          case "sun":
            wd-=1;
            break;
          case "mon":
            wd++;
          case "wed":
            wd+=2;
          }
        }
        System.out.println(wd);
      }

推荐答案

在情况"为"mon" 的末尾，您没有 break; ，因此值是也增加了2

You don't have a break; at the end of case "mon" so value is also incremented by 2

您没想到的流:

0    -1   -1   +1+2  +2 = 3
^     ^    ^   ^     ^
init sat  sun  mon  wed 

添加以下中断将导致输出为1

Adding a break as below will result with output 1

case "mon":
  wd++;
  break;

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