#include<stdio.h>
void main()
{
 int year,month,day;
 int leap;
 printf("please input year,month,day:");
 scanf("%d%d%d",&year,&month,&day);
 switch(month)
 {
  case 12:
   day+=30;
  case 11:
   day+=31;
  case 10:
   day+=30;
  case 9:
   day+=31;
  case 8:
   day+=31;
  case 7:
   day+=30;
  case 6:
   day+=31;
  case 5:
   day+=30;
  case 4:
   day+=31;
  case 3:
   day+=28;
  case 2:
   day+=31;
  case 1:
   day=day;
  default:
   printf("please input error:\n");
   break;
 }
   
 if((year%400==0 || year%4==0 &&year%100!=0) && month>2)
  leap=1;
 else
  leap=0;
 if(leap=1 && month>2)
  day++;
 printf("\nday=%d\n",day);
  
}

#include<stdio.h>
void main()
{
    int year,month,day;
    int leap;
    printf("please input year,month,day:");
    scanf("%d%d%d",&year,&month,&day);
    switch(month)
    {
        case 12:
            day+=30;
        case 11:
            day+=31;
        case 10:
            day+=30;
        case 9:
            day+=31;
        case 8:
            day+=31;
        case 7:
            day+=30;
        case 6:
            day+=31;
        case 5:
            day+=30;
        case 4:
            day+=31;
        case 3:
            day+=28;
        case 2:
            day+=31;
        case 1:
            day=day;break;
        default:
            printf("sorry,please input error!\n");
        
    }
    if(month>=1 && month<=12){
    if((year%400==0 || year%4==0 &&year%100!=0) && month>2)
        leap=1;
    else
        leap=0;
    if(leap=1 && month>2)
        day++;
    printf("\nday=%d\n",day);
    }
    else
        printf("\nbyebye\n");
        
}