帮我写一份输入年月日，输出该年有多少天，该月有多少天的c++代码用switch语法

好的，以下是代码：

#include <stdio.h>

int main() {
    int year, month, day, days_in_month;

    printf("请输入年份: ");
    scanf("%d", &year);

    printf("请输入月份: ");
    scanf("%d", &month);

    switch (month) {
        case 1:
            days_in_month = 31;
            break;
        case 2:
            if ((year % 4 ==  && year % 100 != ) || year % 400 == ) {
                days_in_month = 29;
            } else {
                days_in_month = 28;
            }
            break;
        case 3:
            days_in_month = 31;
            break;
        case 4:
            days_in_month = 30;
            break;
        case 5:
            days_in_month = 31;
            break;
        case 6:
            days_in_month = 30;
            break;
        case 7:
            days_in_month = 31;
            break;
        case 8:
            days_in_month = 31;
            break;
        case 9:
            days_in_month = 30;
            break;
        case 10:
            days_in_month = 31;
            break;
        case 11:
            days_in_month = 30;
            break;
        case 12:
            days_in_month = 31;
            break;
        default:
            printf("输入的月份无效，请输入1-12之间的数字。\n");
            return 1;
    }

    printf("%d年%d月有%d天。\n", year, month, days_in_month);

    return ;
}