在这里插入代码片
#include<stdio.h>
main()
{
    int year,mouth,day,days=0;
    int w,m,d,y;
    printf("请输入年,月,日\n");
    scanf("%d%d%d",&y,&m,&d);
    mouth=m;
    year=y;
    day=d;
    switch(mouth)
        {
        case 1:days=0;break;
        case 2:days=31;break;
        case 3:days=59;break;
        case 4:days=90;break;
        case 5:days=120;break;
        case 6:days=151;break;
        case 7:days=181;break;
        case 8:days=212;break;
        case 9:days=243;break;
        case 10:days=273;break;
        case 11:days=304;break;
        case 12:days=334;break;
    }
    days+=day;
    if(mouth>2&&year%4==0&&year%100!=0||year%400==0)
       days++;
    printf("%d年%d月%d日第%d天",year,mouth,day,days);
    }