C++ Program to calculate date using classes

#include<iostream.h>
#include<conio.h>
#include<stdio.h>
#include<string.h>
class date
{   private: char olddate[20];
     int days;
    public: char colddate[20];
   int day;
   void accp();
   void getdate()
   {  strcpy (colddate,olddate);
      day=days;
      return;
   }
   char newdate(char colddate[], int day);
   void disp();
};
void main()
{ clrscr();
  date d;
  char a[20];int b;
  d.accp();
  strcpy(a,d.colddate);
  b=d.day  ;
  d.newdate(a,b);
  d.disp();
  getch();
}
void date::accp()
{ cout<<"\n enter the old date (dd-mm-yyyy) : ";
  gets(olddate);
  cout<<"\n enter the numbers of days : ";
  cin>>days;
}
char date::newdate(char colddate[], int day)
{ int m=0,y=0;char temp[20];
  do
  {    if (day>=360)
       {  y++;
 day=day-360;
       }
       else
       if (day>=30)
       {  m++;
 day=day-30;
       }
  }while(day>=30);
  colddate[0]=colddate[0]+(day/10);
  colddate[1]=colddate[1]+(day%10);
  colddate[3]=colddate[3]+(m/10);
  colddate[4]=colddate[4]+(m%10);
  colddate[8]=colddate[8]+(y/10);
  colddate[8]=colddate[8]+(y%10);
  return colddate[];
}
void date::disp()
{  cout<<"\n new date is "<<colddate;
}