判断一个时期时间是否正确，输出下一秒的时间

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
using namespace std;

int year=0;
int month=0;
int day=0;
int hour=0;
int minute=0;
int second=0;

//函数声明
void inputDate();
int dayMonth(int );
int leapyear(int );
void nextScond();

int main()
{
while(1)
{
inputDate();
nextScond();
}

return 0;
}

//输入日期,检查日期输入是否正确
void inputDate()
{
int loop;
for(loop=0;loop<3;loop++)
{
cout<<"请输入年-月-日 时：分：秒"<<endl;
cout<<"年：";
cin>>year;
cout<<"月：";
cin>>month;
cout<<"日：";
cin>>day;
cout<<"时：";
cin>>hour;
cout<<"分：";
cin>>minute;
cout<<"秒:";
cin>>second;
if(month<1||month>12)
{
cout<<"月份输入错误！"<<endl;
continue;
}
else if(day<1||day>dayMonth(month))
{
cout<<"日期输入错误！"<<endl;
continue;
}
else if(hour<0||hour>23)
{
cout<<"小时输入错误！"<<endl;
continue;
}
else if(minute<0||minute>59)
{
cout<<"分钟输入错误！"<<endl;
continue;
}
else if(second<0||second>59)
{
cout<<"秒输入错误！"<<endl;
continue;
}
else
{
break;
}
}
}

int dayMonth(int month)
{
switch(month)
{
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: return 31;
case 2:
if(0==(year%4 && 0!=year%100)||0== year%400)
{
return 29;
}
else
return 28;

case 4:
case 6:
case 9:
case 11:
return 30;

}
return 1;
}

//判断是否
int leapyear(int year)
{
if(0 == (year % 4 && 0 != year % 100) || 0 == year %400)
return 1;
else
return 0;
}

//下一秒的日期时间
void nextScond()
{
if(59==second)
{
minute+=1;
second=0;
if(60==minute)
{
hour+=1;
minute=0;
if(24==hour)
{
day+=1;
hour=0;
if(day>dayMonth(month))
{
month+=1;
day=1;
if(13==month)
{
year+=1;
month=1;
}
}
}
}
}
else
second+=1;
cout<<year<<"-"<<month<<"-"<<day<<" "<<hour<<":"<<minute<<":"<<second;
}