#include  < stdio.h >
void  main()
... {
    int a,b,c,sum,leap,flag=1;
    while(flag)
    ...{
    printf("请输入年、月、日(月份前请不要加0!!) ");
    scanf("%d%d%d",&a,&b,&c);
    if(a%4<0||b<=0||b>12||c<=0||c>31)
        printf("我跳起日啊!!你在搞毛!!想死了是吧，在乱来 ");
    else if((a%4==0&&a%100!=0)||(a%400==0))
    ...{
        switch(b)
        ...{
        case 1:sum=0;break;
        case 2:sum=31;break;
        case 3:sum=60;break;
        case 4:sum=91;break;
        case 5:sum=121;break;
        case 6:sum=152;break;
        case 7:sum=182;break;
        case 8:sum=213;break;
        case 9:sum=244;break;
        case 10: sum=274;break;
        case 11:sum=305;break;
        case 12:sum=335;break;
        }
    leap=sum+c;
    printf("您输入的是");
    printf("%d",a);
    printf("年的第%d天! ",sum);
    }
    else
    ...{
        switch(b)
        ...{
        case 1:sum=0;break;
        case 2:sum=31;break;
        case 3:sum=59;break;
        case 4:sum=90;break;
        case 5:sum=120;break;
        case 6:sum=151;break;
        case 7:sum=181;break;
        case 8:sum=212;break;
        case 9:sum=243;break;
        case 10: sum=275;break;
        case 11:sum=304;break;
        case 12:sum=334;break;
        }    
        leap=sum+c;
    printf("您输入的是");
    printf("%d",a);
    printf("年的第%d天! ",sum);
    }
    printf("continue or not(Y/N)? ");
    scanf("%c",&c);
    if(c=='y'||c=='Y')
        flag=0;
    }
}

#include  < stdio.h >
struct  
... {
    int day;
    int month;
    int year;
} date;

void  main()
... {
    int days;
    printf("input day month year: ");
    scanf("%d%d%d",&date.year,&date.month,&date.day);
    switch(date.month)
    ...{
    case 1:days=date.day;break;
    case 2:days=31+date.day;break;
    case 3:days=59+date.day;break;
    case 4:days=90+date.day;break;
    case 5:days=120+date.day;break;
    case 6:days=151+date.day;break;
    case 7:days=181+date.day;break;
    case 8:days=212+date.day;break;
    case 9:days=243+date.day;break;
    case 10:days=273+date.day;break;
    case 11:days=304+date.day;break;
    case 12:days=334+date.day;break;
    }
    if((date.year%4==0&&date.year%100!=0)||(date.year%400==0)&&date.month>=3)
        days=days+1;
    printf("%d ",days);
}

#include  < stdio.h >
struct
... {
    int day;
    int month;
    int year;
} date;

void  main()
... {
    int i,days=0;
    int day_lib[13]=...{0,31,28,31,30,31,30,31,31,30,31,30,31};
    printf("input year month day: ");
        scanf("%d%d%d",&date.year,&date.month,&date.day);
    for(i=0;i<date.month;i++)
        days=days+day_lib[i];
    days=days+date.day;
    if((date.year%4==0&&date.year%100!=0)||(date.year%400==0)&&date.month>=3)
        days=days+1;
    printf("%d ",days);
}