计算日期差值 C实现

#include "stdafx.h"
#include "math.h"
#include <cstdio>
using namespace std;
bool IsRunYear(int y)
{
    bool result=false;
    if(y%4==0&&y%100!=0||y%400==0)
        result=true;
    return result;
}
int MaxDay(int m,int y)
{
    int result;
    if(m==1||m==3||m==5||m==7||m==8||m==10||m==12)
        result=31;
    else if(m==2&&IsRunYear(y))
        result=29;
    else if(m==2&&!IsRunYear(y))
        result=28;
    else 
        result=30;
    return result;
}
long DiffDay(int m,int y)
{
    long val=0;
    while(--m)
    {
        val+=MaxDay(m,y);
    }
    return val;
}
long DiffYear(int minY,int maxY)
{
    long diff=0;
    do
    {
        if(IsRunYear(minY))
            diff+=366;
        else 
            diff+=365;
    }
    while(++minY!=maxY);
    return diff;
}

int main()
{
    int y0,y1,m0,m1,d0,d1;
    long diffDay;
    do
    {
    printf("Please input the first year,month,day between 0000-1-1 and 9999-12-31\n");
    scanf("%d,%d,%d",&y0,&m0,&d0);
    }
    while(!(y0>=0&&y0<=9999&m0>=1&&m0<=12&d0>=1&&d0<=MaxDay(m0,y0)));
    do
    {
    printf("Please input the second year,month,day between 0000-1-1 and 9999-12-31\n");
    scanf("%d,%d,%d",&y1,&m1,&d1);
    }
    while(!(y1>=0&&y1<=9999&m1>=1&&m1<=12&&d1>=1&&d1<=MaxDay(m1,y1)));
    if(y0==y1&&m0==m1)
        diffDay=abs(d0-d1);
    else if (y0==y1)
            {
                long day1=DiffDay(m0,y0)+d0;
                long day2=DiffDay(m1,y1)+d1;
                diffDay=abs(day1-day2);
            }
    else 
    {
        int minY,maxY;
        long day1,day2;
        if(y0>y1)
        {
            minY=y1;
            maxY=y0;
            day1=DiffDay(m1,y1)+d1;
            day2=DiffDay(m0,y0)+d0;
        }
        else 
        {
            minY=y0;
            maxY=y1;
            day1=DiffDay(m0,y0)+d0;
        day2=DiffDay(m1,y1)+d1;
        }
        long day3=DiffYear(minY,maxY);
        diffDay=day3+day2-day1;
    }
    printf("The diff day=%ld",diffDay);
    return 0;
}