星期几--蓝桥杯

# include <stdio.h>
int yday(int year);
int main(void)
{
    int year;
    int n;    //是星期日的天数
    int w;    //星期几
    
    n = 0;
    w = 6;
    for(year = 1950; year < 2013; year++) {
        w = (yday(year) % 7 + w) % 7;
        if(w == 0) {
            n++;
        }
    }
    printf("%d", n);
}
int yday(int year)
{
    if((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) {
        return 366;
    } else {
        return 365;
    }
}