Addition and subtraction of complex numbers using class in C++ - c++

Question

I have here a code that is supposed to ask the user two sets of real and imaginary numbers.
#include <iostream>
using namespace std;
class Complex {
public:
double r;
double i;
public:
Complex();
void add(Complex, Complex);
void subtract(Complex, Complex);
void print();
};
Complex::Complex() {
r = i = 0;
}
void Complex::add (Complex op1, Complex op2) {
r = op1.r+op2.r;
i = op1.i+op2.i;
}
void Complex::subtract (Complex op1, Complex op2) {
r = op1.r-op2.r;
i = op1.i-op2.i;
}
void Complex::print () {
cout << r << i;
}
int main () {
Complex operand1, operand2, result;
cout << "Input real part for operand one: " << endl;
cin >> operand1.r;
cout << "Input imaginary part for operand one: " << endl;
cin >> operand1.i;
cout << "Input real part for operand two: " << endl;
cin >> operand2.r;
cout << "Input imaginary part for operand two: " << endl;
cin >> operand2.i;
result.add(operand1, operand2);
cout << "The sum is " << result.add << endl;
result.subtract(operand1, operand2);
cout << "The difference is " << result.subtract << endl;
}
However, when I compiled the program, lots of errors are displayed (std::basic_ostream) which I don't even get.
Another issue I'm having is in the function void::Complex print. There should be a condition inside cout itself. No if-else. But I have no idea what to do.
The program must run like this:
Input real part for operand one: 5
Input imaginary part for operand one: 2 (the i for imaginary shouldn't be written)
Input real part for operand two: 8
Input imaginary part for operand two: 1 (again, i shouldn't be entered)
/then it will print the input(ed) numbers/
(5, 2i) //this time with an i
(8, 1i)
/then the answers/
The sum is 13+3i.
The difference is -3, 1i. //or -3, i
Please help me! I'm new in C++ and here in stackoverflow and your help would be very appreciated. Thank you very much!

Answer 1

The line
cout << "The sum is " << result.add << endl;
is incorrect, as add is a method so result.add will be a pointer to that method, and cout does not know how to handle it - which makes the compiler spit it out.
Change the line to
cout << "The sum is ";
result.print();
cout << endl;
You need to do the same for the line
cout << "The difference is " << result.subtract << endl;
As to coding style, the two methods are overwrting an existing complex number. Perhaps having a the function like this would be better
Complex &Complex::add (const Complex &op) {
r += op.r;
i += op.i;
return *this;
}
This will enable you to chain additions together and also just add a complex number to the existing complex number.
In addition you could make the class variables r and i private. This will require an alternative constructor:
Complex:Complex(double real, double imaginary) : r(real), i(imaginary) {};
Finally you may wish to consider operator overloading - I am sure you can google that to find a reasonable tutorial.

Answer 2

In main, after you call result.add, you put the same function in the cout stream when it doesn't return anything. I think you meant to write cout << "the sum is " << result.print();

Answer 3

You are already using the std:: namespace. Just use the complex number library in it like this answer suggests: Addition of complex numbers using classes

Answer 4

#include <iostream>
using namespace std;
class Complex {
public:
double r;
double i;
public:
void add(Complex, Complex);
void subtract(Complex, Complex);
void print();
};
void Complex::add (Complex op1, Complex op2) {
r = op1.r + op2.r;
i = op1.i + op2.i;
}
void Complex::subtract (Complex op1, Complex op2) {
r = op1.r - op2.r;
i = op1.i - op2.i;
}
void Complex::print () {
cout << "("<<r<<", " << i <<")";
}
int main () {
Complex operand1, operand2, result;
cout << "\nInput real part for operand one: " << endl;
cin >> operand1.r;
cout << "Input imaginary part for operand one: " << endl;
cin >> operand1.i;
cout << "Input real part for operand two: " << endl;
cin >> operand2.r;
cout << "Input imaginary part for operand two: " << endl;
cin >> operand2.i;
cout << "\nThe sum is ";
result.add(operand1, operand2);
result.print();
cout << "\nThe difference is ";
result.subtract(operand1, operand2);
result.print();
}