text: #include<stdio.h>
  
  int global_v = 5;
  int test_switch()
  {
      switch(global_v){
          case 1: printf("1");break;
          case 5: printf("5");break;
          case 7: printf("7");break;
          default: printf("fail");
      }
  }
  
  int main(int argc, char* argv[])
  {
      test_switch();
  }
  