#include <iostream>
using namespace std;

class Date
{
private:
	int day, month, year;

public:
	Date(int inMonth, int inDay, int inYear)
		:month(inMonth), day(inDay), year(inYear)
	{
		cout << "Date is created!" << endl; // I put this in to see the constructor work
	}

	Date& operator ++ () // when I leave off the & the result is the same, why would I use it?
	{
		++day;
		return *this;
	}

	Date& operator -- () // when I leave off the & the result is the same, why would I use it?
	{
		--day;
		return *this;
	}

	void DisplayDate()
	{
		cout << month << " / " << day << " / " << year << endl;
	}
};

int main()
{
	Date holiday(12, 25, 2016); // Dec 25, 2016

	cout << "The date object is initiated to: ";
	holiday.DisplayDate();

	++holiday; // move data ahead by a day
	cout << "Date after prefix-increment is: ";
	holiday.DisplayDate();

	--holiday; // move date backwards by a day
	cout << "Date after a prefix-decrement is: ";
	holiday.DisplayDate();

	return 0;
}

// Example program
#include <iostream>
#include <string>

//
// Pre-increment operator implemented two ways (e.g. ++obj)
//

class ThingPlusRef {
  public:
    ThingPlusRef() : day(0) {}
  	ThingPlusRef& operator ++()
	{
		++day;
		return *this;
	}
	
	int day;
};

class ThingPlusCopy {
  public:
    ThingPlusCopy() : day(0) {}
  	ThingPlusCopy operator ++()
	{
		++day;
		return *this;
	}
	
	int day;
};

int main()
{
    using std::cout;
    
    ThingPlusCopy t1;
    ThingPlusCopy t1_copy = ++t1;
    ++t1_copy;
    
    cout << "t1.day      = " << t1.day << '\n';
    cout << "t1_copy.day = " << t1_copy.day << '\n';
    
    ThingPlusRef t2;
    ThingPlusRef& t2_ref = ++t2;
    ++t2_ref;
    
    cout << "t2.day      = " << t2.day << '\n';
    cout << "t2_ref.day  = " << t2_ref.day << '\n';
}