输入日期判断某年第几天

#include<stdio.h>
int main(){
int y;
int m;
int d;
int a;
int b;
int c;
printf("请输入2000-2500之间的日期（年、月、日）:\n");
scanf("%d%d%d",&y,&m,&d);
printf("%d年%d月%d日\n",y,m,d);
a=y%4;
b=y%400;
c=y%100;
if(y>=2000&&y<=2500){
if(b==0){
printf("%d年是闰年,%d年%d月%d日是%d年的第%d天\n",y,y,m,d,y);
}else if(a==0&&b!=0&&c!=0){
printf("%d年是闰年,%d年%d月%d日是%d年的第%d天\n",y,y,m,d,y);
}else if(a==0&&b!=0&&c==0){
printf("%d年是平年,%d年%d月%d日是%d年的第%d天\n",y,y,m,d,y);
}else{
printf("%d年是平年,%d年%d月%d日是%d年的第%d天\n",y,y,m,d,y);
}
}else{
printf("您输入的日期不符合要求！");
}
return 0;
}