C++ switch开关语句

C++ 开关语句从多个条件中执行一个语句。它类似于C++中的if-else-if梯形语句。

switch(expression){    
case value1:    
 //code to be executed;    
 break;  
case value2:    
 //code to be executed;    
 break;  
......    

default:     
 //code to be executed if all cases are not matched;    
 break;  
}  

C++ Switch示例

#include <iostream>
using namespace std;
int main () {
       int num;
       cout<<"Enter a number to check grade:";  
       cin>>num;
           switch (num)  
          {  
              case 10: cout<<"It is 10"; break;  
              case 20: cout<<"It is 20"; break;  
              case 30: cout<<"It is 30"; break;  
              default: cout<<"Not 10, 20 or 30"; break;  
          }  
    }  

输出：

Enter a number:
10
It is 10

输出:

Enter a number:
55
Not 10, 20 or 30