´ÞÀÇ ³¯¼ö hint

-if ¹®À¸·Î ±¸Çö
   int year,month;

   scanf("%d %d",&year,&month);

   if ( month==1 ||month==3||month==5||month==7||month==8||month==10||month==12 ) {
      printf("31\n");
   }else if ( month==4 || month==6 || month==9 || month==11) {
      printf("30\n");
   }else {
      if (year % 4 ==0 && year%100 != 0 || year % 400 ==0){
         printf("29\n");
      }else {
         printf("28\n");
      }
   }
   
-switch ¹®À¸·Î ±¸Çö
   int year,month;

   scanf("%d %d",&year,&month);

   switch ( month ) {
      case 1:
      case 3:
      case 5:
      case 7:
      case 8:
      case 10:
      case 12:
         printf("31\n");break;
      case 4:
      case 6:
      case 9:
      case 11:
         printf("30\n");break;
      case 2:
         if ( year % 4 == 0 && year % 100 != 0 || year % 400 == 0 ) {
            printf("29\n");
         }else {
            printf("28\n");
         }
   }
   

[ȨÀ¸·Î]  [µÚ ·Î]