C语言-三天打鱼两天晒网

#include<stdio.h>
//起点为1990.1.1，要求小于1990年或者不合法的输入皆输出Invalid input
const int START=1990;
const int MONTH[2][13]={{0,31,28,31,30,31,30,31,31,30,31,30,31},{0,31,29,31,30,31,30,31,31,30,31,30,31}};
int BetDays(int,int,int);
int IsLeap(int year);
int main()
{
    int bet;
    int year,month,day;
    int result=0;
    scanf("%d %d %d",&year,&month,&day);
    if(year<1990)printf("Invalid input\n");
    else if(month<1||month>12)printf("Invalid input\n");
    else if(day<1||day>MONTH[IsLeap(year)][month])printf("Invalid input\n");
    else{
        bet=BetDays(year,month,day);
        result=bet%5;
        switch(result)
        {
        case 1:
        case 2:
        case 3:
            printf("He is working");
            break;
        case 4:
        case 0:
            printf("He is having a rest");
            break;
        }
    }
    return 0;
}

int IsLeap(int year)
{
    return (year%400==0)||((year%4==0)&&(year%100!=0));
}
int BetDays(int year,int month,int day)
{
    int bet=0;
    int i,j;
    int x,y;
    for(i=1990;i<year;i++){
        for(j=1;j<13;j++){
            bet+=MONTH[IsLeap(i)][j];
        }
    }
    for(x=1;x<month;x++){
        bet+=MONTH[IsLeap(year)][x];
    }

    bet+=day;
    return bet;
}