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C++嵌套switch語句

有可能有一個switch作為外switch語句序列的一部分。即使在內外switch的case的常數包含共同的值,冇有衝突將出現。

C++規定,至少允許256層嵌套switch語句。

語法

嵌套switch語句的語法如下:

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': // ...
}

例子:

#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;
}

這將產生以下結果:

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