题解 | #获得月份天数#

#include <stdio.h>

int IsRunNian(int a) {//是否是闰年的判断
    int flag = 0;
    if (a % 100 == 0) {
        if (a % 400 == 0) flag = 1;
    } 
    else {
        if (a % 4 == 0) flag = 1;
    }
    return flag;
}

int main() {
    int year, month;
    while (scanf("%d %d", &year, &month) != EOF) { 
        if(month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) printf("31\n");
        else if(month == 2){ //2月需要判断是否是闰年
            if(IsRunNian(year) == 1) printf("29\n");
            else printf("28\n");
        }
        else printf("30\n");
    }
    return 0;
}