710

int day_of_year(int year,int month,int day)
{
    int k,leap;
    int tab[2][13]={
        {0,31,28,31,30,31,30,31,31,30,31,30,31},
        {0,31,29,31,30,31,30,31,31,30,31,30,31}
    };
    leap=(year % 4==0 && year%100!=0 || year%400==0);
    for(k=1;k<month;k++)
        day=day + tab[leap][k];
    return day;
}