C语言编程问题求解答

#include <stdio.h>
#include <stdlib.h> //system("pause")

main()
{
    int year, month, day, total, leap; //total总天数 ,leap用于闰年的2月天数
    scanf("%d%d%d", &year, &month, &day);
    if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) //判断是否闰年，闰年2月多一天，所以闰年leap为1，平年为leap为0。
    {
        leap = 1;
    }
    else
    {
        leap = 0;
    }

    switch (month) //根据月份计算对应的最终天数。
    {
    case 1:
        total = day;
        break;
    case 2:
        total = 31 * 1 + day;
        break;
    case 3:
        total = 31 * 1 + 28 + leap + day;
        break;
    case 4:
        total = 31 * 2 + 28 + leap + day;
        break;
    case 5:
        total = 31 * 2 + 28 + leap + 30 * 1 + day;
        break;
    case 6:
        total = 31 * 3 + 28 + leap + 30 * 1 + day;
        break;
    case 7:
        total = 31 * 3 + 28 + leap + 30 * 2 + day;
        break;
    case 8:
        total = 31 * 4 + 28 + leap + 30 * 2 + day;
        break;
    case 9:
        total = 31 * 5 + 28 + leap + 30 * 2 + day;
        break;
    case 10:
        total = 31 * 5 + 28 + leap + 30 * 3 + day;
        break;
    case 11:
        total = 31 * 6 + 28 + leap + 30 * 3 + day;
        break;
    case 12:
        total = 31 * 6 + 28 + leap + 30 * 4 + day;
        break; //12月之前的11个月中有6个31天，4个30天，2月为28天+leap。
    }

    if (year >= 1 && year <= 9999 && month >= 1 && month <= 12 && day >= 1 && day <= 31) //判断输入是否正解，年份最大为9999，可自行更改。
    {
        printf("%d\n",total);
    }
    else
    {
        printf("\n\t错误\n\n");
    }
    return 0;
}

#include<stdio.h>

int dm(int year,int month, int day)
{
        int flag=0;
        if((year%4==0 && year%100!=0) || (year%400==100))flag = 1;
        else flag =0;
        int a=0;
        switch(month-1)
        {
                case 11 :a+=30;
                case 10 :a+=31;
                case 9 :a+=30;
                case 8 :a+=31;
                case 7 :a+=31;
                case 6 :a+=30;
                case 5 :a+=31;
                case 4 :a+=30;
                case 3 :a+=31;
                case 2 :a+=28+flag;
                case 1 :a+=31;break;
                default :printf("Please input others\n");
        }
        a +=day;
        printf("%d \n",a,year);
}
int main()
{
        int day,month,year;
        printf("请输入年 月 日:\n");
        scanf("%d %d %d",&year,&month,&day);
        dm(year,month,day);
       return 0;
}