今天写课后题看到一个给你某年某月某日让你算是一年中的第几天，做完之后想试试如果给你一年中的第几天，你能不能算出是第几个月第几天，于是我用半个小时写下了一下这个代码，请大家给指导一下，有什么漏洞请尽可批评，谢谢大家！



main()
{int year,day,i,j,month,month_tab[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
month=1;
printf("input year,day\n");
scanf("%d,%d",&year,&day);
printf("\n");
if(day<=31)
printf("Today is year %d month %d day %d \n",year,month,day);
else {if(((year%400==0)||(year%4&&year%100!=0))&&(day>=60))
     day=day-1;
     for(i=1;i<=12;i++)
     {
       day-=month_tab[i];
       if(day<=28||day==30||day==31)
       {month=i+1;
        break;
        }
      }
      printf("Today is year %d month %d day %d \n",year,month,day);
      }

getch();
}

/* VC环境 */
#include <stdio.h>

int main (void)
{
    int yearInput;
    int daysInput;
    int monthDay[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
    int month = 0;
    int day;

    //输入年份
    printf("Please insert the year: ");
    scanf("%d", &yearInput);
    
    //闰年二月份加一天
    if(yearInput % 4 == 0)
        monthDay[1]++;

    //输入天数
    printf("Insert the numbers of days: ");
    scanf("%d",&daysInput);

    for(int i = 0; i < 12; i++)
    {
        //月份增一，如果还有足够的天数就减去
        month++;
        if(daysInput > monthDay[i])
            daysInput -= monthDay[i]; 

        //剩下的转交给日数，强行结束   
        else
        {
            day = daysInput;
            break;
        }

    }//循环结束

    //输出结果
    printf("Date : %d - %d - %d\n\n", yearInput, month, day);

    return 0;
}

#include<stdio.h>
void main()
{
    int s(int yea,int mon,int day);
    int yea,mon,day,t;
    printf("input a day number include the year,the month and the day:");
    scanf("%d,%d,%d",&yea,&mon,&day);
    putchar('\n');
    t=s(yea,mon,day);
    printf("%d,%d,%d is the %d day of this year\n",yea,mon,day,t);
}
int s(int yea,int mon,int day)
{
    int a[12]={31,29,31,30,31,30,31,30,31,30,31,30};
    int i,sum=0;
    if((yea%4==0&&yea%100!=0)||yea%400==0)
        a[1]=28;
    for(i=0;i<mon-1;i++)
        sum+=a[i];
    sum+=day;
    return sum;
}

3楼受教了

晕，貌似我要的和你发的是相反的哦，呵呵，不过还是谢谢大侠了，的确编的不错！还望以后多多指教,谢谢……