DATE DIFFERENCE IN C++

#include<iostream.h>
#include<conio.h>
class Date
{
public:
   int d1,d2,m1,m2,y1,y2;
   int d,m,y;
 void insert()
 {
  cout<<"Enter the first date in dd/mm/yy format"<<endl;
  cin>>d1>>m1>>y1;
  if(d1>30 || m1>12)
   cout<<"Please enter a valid input"<<endl;
  cout<<"Enter the second date in dd/mm/yy format"<<endl;
  cin>>d2>>m2>>y2;
  if(d2>30 || m2>12)
   cout<<"Please enter a valid input"<<endl;
 }
 void calculate()
 {
  if(d1>d2)
  {
   d=(d2+30)-d1;
   m1=m1+1;
  }
  else
   d=d2-d1;
  if(m1>m2)
  {
   m=(m2+12)-m1;
   y1=y1+1;
  }
  else
   m=m2-m1;
  y=y2-y1;
 }
 void show()
 {
  cout<<"Difference between:"<<endl;
  cout<<d1<<"/"<<m1<<"/"<<y1<<"and"<<d2<<"/"<<m2<<"/"<<y2<<endl;
  cout<<y<<"year"<<'\t'<<m<<"month"<<'\t'<<d<<"day";
 }
};
void main()
{
 Date ob;
 clrscr();
 ob.insert();
 ob.calculate();
 ob.show();
 getch();
}

                                             OUTPUT