# include<iostream.h>
# include<stdlib.h>
# include<time.h>
class date{
    public:
    void trayy()
    {days[0]=31,days[1]=28,days[2]=31,days[3]=30,days[4]=31,days[5]=30,days[6]=31,
    days[7]=31,days[8]=30,days[9]=31,days[10]=30,days[11]=31;
    }
    void one(int a,int b,int c)
    {year=a,month=b,day=c;}
    void now()
    {time_t nowtime;
     struct tm *p;
     time(&nowtime);
     p=localtime(&nowtime);
     year=1900+p->tm_year,month=1+p->tm_mon,day=p->tm_mday;
    }
    void output()
    {   
        if((year%4==0)&&(year%100!=0)||(year%400==0))
        days[1]++;
        while(1)
        {if(getch=='+')  //为什么在这里会有错?提示error C2065: 'getch' : undeclared identifier
        {day=day+1;
            if(day>days[month-1])
            month=month+1,day=1;
            if(month>12)
            year=year+1,month=1,day=1;
             cout<<year<<month<<day<<endl;
          }
        if(getch=='0')//而这里同样有getch却没错?
        exit(0);
        }
    }
    private:
    int year,month,day;
    int days[12];
};
void main()
{   
    int a,b,c;
    date op;
     cout<<"need input data? yes press 1 no press 2"<<endl;
    cin>>a;
    if(a==1)
    {    op.trayy();
        cin>>a>>b>>c;
         op.one(a,b,c);
         op.output();
    }
    if(a==2)
    {    op.trayy();
        op.now();
        op.output();
    }
   
}
一个日期的C++,大家帮忙看一下,我实在不知道为什么会这样

不是在头文件里加了".h",就不用加using namespace std;了吗?

getch不是从键盘上获取一个值吗?这不是本来就有的函数?
while(1)是对加一天日期的处理,后面有一个getch=='0',可以退出的啊