1070.今年的第几天？

#include<iostream>
using namespace std;
#define ISYEAP(x) x%100!=0 && x%4==0 || x%400==0 ? 1: 0

int dayofmonth[13][2]={
     0,0,
     31,31,
     28,29,
     31,31,
     30,30,
     31,31,
     30,30,
     31,31,
     31,31,
     30,30,
     31,31,
     30,30,
     31,31
};

struct date{
    int day;
    int month;
    int year;
    void nextday(){
        day++;
        if(day>dayofmonth[month][ISYEAP(year)]){
            month++;
            if(month>12){
                month=1;
                year++;
            }
        }
    }
};

int buf[3001][13][32];

int main(){
    date temp;
    int cnt=0;
    temp.day=1;
    temp.year=0;
    temp.month=1;
    while(temp.year!=3001){
        buf[temp.year][temp.month][temp.day]=cnt;
        temp.nextday();
        cnt++;
    }
    int d,m,y;
    while(cin>>y>>m>>d){
        cout<<buf[y][m][d]-buf[y-1][12][31]<<endl;
    }
    return 0;
}