运行 ID: 58

Main.cc: In function ‘int main()’:
Main.cc:18:3: error: duplicate case value
   case 1:printf("December");break;
   ^~~~
Main.cc:7:3: note: previously used here
   case 1:printf("January");break;
   ^~~~
Main.cc:5:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&a);
  ~~~~~^~~~~~~~~