OPERATOR OVERLOADING - C++ Program to create a class called DATE.

Write a C++ program to create a class called DATE. Accept two valid dates in the form dd/mm/yy. Implement the following operations by overloading the + and - operators. After every operation display the results by overloading the operator <<.

i)no_of_days=d1 -d2; where d1 and d2 are date objects, d1>=d2 and no_of_days is an integer.

ii)d2=d1+no_of_days; where d1 is a DATE object and no_of_days is an integer.

#include<iostream.h>
#include<process.h>
#include<conio.h>
//class declaration
class date
{
  private:
  int mm,dd,yy;
  public:
  void getdate();
  int operator -(date);
  date operator +(int);
};
// Member function to accept the date from the user
void date::getdate()
{
  cout<<"enter a valid date(dd mm yy)\n";
  START:
  cin>>dd>>mm>>yy;
  if((mm==2) && (dd>29))
  {
    cout<<"wrong input!!!\n";
    cout<<"\nenter the date again....\n";
    goto START;
  }
  if((mm>12)||(dd>31))
  {
    cout<<"wrong input!!!\n";
    cout<<"\nenter the date again....\n";
    goto START;
  }
  if((mm==4||mm==6||mm==9||mm==11) && (dd>30))
  {
    cout<<"wrong input!!!\n";
    cout<<"\nenter the date again....\n";
    goto START;
  }
  if((yy%4)!=0 && (mm==2) && (dd>28))
  {
    cout<<"wrong input!!!\n";
    cout<<"\nenter the date again....\n";
    goto START;
  }
}
// operator overloaded function to find
// the no. of days between two dates
int date::operator -(date d2)
{
  int i,nod1,nod2,nody,lc,no_of_days;
  nod1=nod2=lc=0;
  for(i=1;i<mm;i++)
  {
    if(i==1||i==3||i==5||i==7||i==8||i==10||i==12)
      nod1+=31;
    else if(i==2)
      nod1+=28;
    else
      nod1+=30;
  }
  nod1+=dd;
  for(i=1;i<d2.mm;i++)
  {
    if(i==1||i==3||i==5||i==7||i==8||i==10||i==12)
      nod2+=31;
    else if(i==2)
      nod2+=28;
    else
      nod2+=30;
  }
  nod2+=d2.dd;
  nody=(yy-d2.yy)*365;
  for(i=d2.yy;i<yy;i++)
    if((i%4)==0)
      lc++;
  int y4=yy-d2.yy;
  while(y4>400)
  {
    lc++;
    y4-=400;
  }
  if((mm>2) && (yy%4)==0)
    lc++;
  if((d2.mm>2) && (d2.yy%4)==0)
    lc--;
  no_of_days=nody+nod1-nod2+lc;
  if(no_of_days>0)
  {
    cout<<"total number of days between these dates is=";
    return(no_of_days);
  }
  else
    return(no_of_days);
}
/* operator overloaded function to find
   the new date when no. of days are added to a
   particular date.*/
date date::operator +(int nd)
{
  date dd3;
  while(nd>365)
  {
    yy++;
    nd-=365;
  }
  while(nd>30)
  {
    if(mm==1||mm==3||mm==5||mm==7||mm==8||mm==10||mm==12)
    {
      nd-=31;
      mm++;
    }
    else if(mm==2)
    {
      nd-=28;
      mm++;
    }
    else
    {
      nd-=30;
      mm++;
    }
    if(mm>12)
    {
      yy++;
      mm=1;
    }
  }
  dd=dd+nd;
  if(dd>30)
  {
    if(mm==4||mm==6||mm==9||mm==11)
    {
      mm++;
      dd-=30;
    }
    else if(mm==2)
    {
      mm++;
      dd-=28;
    }
    else if(dd>31)
    {
      mm++;
      dd-=31;
    }
    if(mm>12)
    {
      yy++;
      mm=1;
    }
  }
  dd3.mm=mm;
  dd3.dd=dd;
  dd3.yy=yy;
  cout<<"new date is:";
  cout<<dd<<"-"<<mm<<"-"<<yy<<endl;
  return(dd3);
}
//main function
void main()
{
  clrscr();
  int res,num;
  date dd1,dd2;
  BEGIN:
  dd1.getdate();
  dd2.getdate();
  res=dd1-dd2;
  if(res<0)
  {
    cout<<"\nthe first date should be ";
    cout<<"greater than the second date\n";
    cout<<"so enter the dates again\n";
    goto BEGIN;
  }
  cout<<res;
  cout<<"\nenter the no. of days to be ";
  cout<<"added to the FIRST date:";
  cin>>num;
  dd2=dd1+num;
  getch();
}

OUTPUT