是得要告诉第一天是做什么的,是打鱼还是晒网.并且要给出具体的哪天(打鱼的第几天或是晒网的第几天).

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

void main()
{
    struct date today,term;
    int yearday,year,day;
    printf(\"Enter year/month/day:\");
    scanf(\"%d%d%d\",&today.year,&today.month,&today.day);  /*输入日期*/
    term.month=12;               /*设置变量的初始值：月*/
    term.day=31;                 /*设置变量的初始值：日*/
    for(yearday=0,year=1990;year<today.year;year++)
    {
        term.year=year;
        yearday+=days(term);     /*计算从1990年至指定年的前一年共有多少天*/
    }
    yearday+=days(today);       /*加上指定年中到指定日期的天数*/
    day=yearday%5;               /*求余数*/
    if(day>0&&day<4) printf(\"he was fishing at that day.\n\");   /*打印结果*/
    else printf(\"He was sleeping at that day.\n\");
}

int days(struct date day)
{
    static int day_tab[2][13]=
            {{0,31,28,31,30,31,30,31,31,30,31,30,31,},      /*平均每月的天数*/
             {0,31,29,31,30,31,30,31,31,30,31,30,31,},
    };
    int i,lp;
    lp=day.year%4==0&&day.year%100!=0||day.year%400==0;
      /*判定year为闰年还是平年，lp=0为平年，非0为闰年*/
    for(i=1;i<day.month;i++)            /*计算本年中自1月1日起的天数*/
        day.day+=day_tab[lp][i];
    return day.day;
}