C++ 嵌套开关语句

可以将开关作为外部开关语句序列的一部分。即使内部和外部开关的case常量包含相同的值，也不会出现冲突。

C++规定开关语句的嵌套层数至少允许为256级。

语法

嵌套开关语句的语法如下所示：

switch(ch1) {
   case 'A': 
      cout << "This A is part of outer switch";
      switch(ch2) {
         case 'A':
            cout << "This A is part of inner switch";
            break;
         case 'B': // ...
      }
      break;
   case 'B': // ...
}

示例

#include <iostream>
using namespace std;

int main () {
   // local variable declaration:
   int a = 100;
   int b = 200;

   switch(a) {
      case 100: 
         cout << "This is part of outer switch" << endl;
         switch(b) {
            case 200:
               cout << "This is part of inner switch" << endl;
         }
   }
   cout << "Exact value of a is : " << a << endl;
   cout << "Exact value of b is : " << b << endl;

   return 0;
}

这将产生以下结果−

This is part of outer switch
This is part of inner switch
Exact value of a is : 100
Exact value of b is : 200