C++嵌套switch语句

#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;
}