Difference between two dates C++

[hughng92]

I am trying to solve a problem that asks me to give the total days between two dates. I have to take care of the some matters between those two dates such as leap years and the way of inputting the years by the users. (For example, if you input 1 and 17, the code will still give you the difference is 16 years (2017 - 2001 = 16). I am not supposed to change ANYTHING inside the main() function. Here is my code.

  #include <iostream>
#include <cmath>

using namespace std;

class date
{
	private:
	int m;
	int d;
	int y;
	
	public:
	date();
	date(int, int, int);
	int countLeapYears(date&);
	int getDifference1(date&);
	int getDifference2(date&);
	
	
};

int main()
{
	int day, month, year;
	char c;
	
	cout << "Enter a start date: " << endl;
	cin >> month >> c >> day >> c >> year;
	
	date start = date(month, day, year);
	
	cout << "Enter an end date: " << endl;
	cin >> month >> c >> day >> c >> year;
	
	date end = date(month, day, year);
	
	int duration = end - start;
	
	cout << "The number of days between those two dates are: " << duration << endl;
	
	return 0;
}

date::date()
{
	m = 0;
	d = 0;
	y = 0;
}

date::date(int a, int b, int c)
{
	m = a;
	d = b;
	y = c;
}

const int monthDays[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

int date::countLeapYears(date& d)
{
    int years = d.y; 
    if (d.m <= 2)
        years--;   
    return years / 4 - years / 100 + years / 400;
}

int date::getDifference1(date& start)
{

    int n1 = start.y*365 + start.d;
   
    for (int i=0; i<start.m - 1; i++)
    {
      n1 += monthDays[i];
      n1 += countLeapYears(start);
    }
     
    return n1;
}

int date::getDifference2(date& end)
{
    int n2 = end.y*365 + end.d;
   
    for (int i=0; i<end.m - 1; i++)
    {
      n2 += monthDays[i];
      n2 += countLeapYears(end);
    } 
    return n2;
}

I have an issue with my code above, and I need your help please. When I ran it, it said invalid binary operation between "date" and "date". Now, I assume that when I initialized int duration = end - start, I should have got a number. I guess what I am doing wrong here is I failed to convert the (end - start) date type into integer. I thought my function getDifference already took care of that issue. Somehow, it appeared that I did not take care of that issue.

[xismn]

Your date class doesn't overload operator-, so it won't know how to perform the operation on line 38.

Since you aren't allowed to change the main function, you'll have to overload operator-. Since you already have a getDifference member function, all you'll really have to do is invoke that.

Also, maybe you can tell me why you have two getDifference functions?