Need help w/simple program

Could you please tell me what I am doing wrong? I am trying to overload the + operator, and output the sum of the 5 numbers (a, b, c, d, e).

Code:

#include <iostream.h>
#include <math.h>

class BigInteger{
private:
	
public:
	double a, b, c, d, e;
	void initial();
	//sum(BigInteger &one, BigInteger &two);
	friend BigInteger operator+(BigInteger);
};

void BigInteger::initial()
{
	cout << "Please enter 5 integers: " ;
	cin >> a >> b >> c >> d >> e;
}

BigInteger operator+(BigInteger &num)
{
	//BigInteger num;
	num = ;         // what do I put here???
	return num;
}

int main()
{
	BigInteger one, two;
	one.initial();
	
	cout << one.a << one.b << one.c << one.d << one.e <<endl;
	
	return 0;

}

Code:

BigInteger operator+(BigInteger &num)
{
	//BigInteger num;
	num = ;         // what do I put here???
	return num;
}

Well it´s up to you to deside! What du you want it do when you add???

I would guess that you want to add all data-members in the class and return the result. One solution may be

Code:

BigInteger operator+(BigInteger &num)
{
                BigInteger result_of_addition;
                result_of_addition.a = a + num.a;
                result_of_addition.b = b + num.b;
                result_of_addition.c = c + num.c;
                result_of_addition.d = d + num.d;
                result_of_addition.e = e + num.e;
	return result_of_addition;
}

Your question isn´t easy to answer, but if you describe it more in detail it certainly would be easier for me to help you.

Thanks Ripper....I want to enter 5 integers (a thru e), then add them together and print the result.

Code:

//...
BigInteger BigInteger :: operator++() { //changed from friend function to member function
return a+b+c+d+e;
}
//...
int main() {
BigInteger ob1;
ob1.initial();
cout<<++ob1;
return 0;
}

The above may be wrong cos im incompetent
Well I tried.

Code:

...
BigInteger BigInteger :: operator++() { //changed from friend function to member function
return a+b+c+d+e;
}
...

hmmm well it depends again how you want it to behave. For instance if I would overload the ++ operator I would try it to mimic the built in types. My version would go something like this

Code:

const BigInteger & BigInteger :: operator++() 
{ 
a++; b++; c++; d++; e++;
return *this;
}

This would increment the data-members by one and return a const refernce (more efficient then returing a copy of it). Now it is possible to e.i

Code:

...
BigInteger one, two;
one.initial();
two = ++one;
...

Also I would encourage you to use the constructor insteed of your initial member-function. The constructor is there so you can initialize the data-members.