A small programming challenge for the purpose of learning C++.

calculator.cpp

#include <iostream>
using namespace std;

class ComplexNumber {
    public:
        double real;
        double imag;

        ComplexNumber(double r, double i) {
            real = r;
            imag = i;
        }

        void print() {
            cout << endl << "Result: " << endl << " Real: " << real << endl << " Imaginary: " << imag << endl;
        }

        ComplexNumber operator+(ComplexNumber cn2) {
            return ComplexNumber(this->real + cn2.real, this->imag + cn2.imag);
        }
        ComplexNumber operator-(ComplexNumber cn2) {
            return ComplexNumber(this->real - cn2.real, this->imag - cn2.imag);
        }
        ComplexNumber operator*(ComplexNumber cn2) {
            return ComplexNumber(this->real * cn2.real, this->imag * cn2.imag);
        }
        ComplexNumber operator/(ComplexNumber cn2) {
            return ComplexNumber(this->real / (double) cn2.real, this->imag / (double) cn2.imag);
        }
};

int main() {
    cout << endl << "-- Calculator --" << endl << endl;

    double x1, y1, x2, y2;
    cout << "Enter the first complex number: " << endl;
    cout << "Enter real: ";
    cin >> x1;
    cout << "Enter imaginary: ";
    cin >> y1;
    cout << "Enter the second complex number: " << endl;
    cout << "Enter real: ";
    cin >> x2;
    cout << "Enter imaginary: ";
    cin >> y2;

    ComplexNumber cn1(x1, y1);
    ComplexNumber cn2(x2, y2);

    cout << endl << "Thank you." << endl << endl;

    while (true) {
        cout << "(1) Add" << endl << "(2) Subtract" << endl << "(3) Multiply" << endl << "(4) Divide" << endl << "Enter the number of the operation you'd like to perform: ";
        int op;
        cin >> op;

        string result = "";
        switch (op) {
            case 1:
                (cn1 + cn2).print();
                break;
            case 2:
                (cn1 - cn2).print();
                break;
            case 3:
                (cn1 * cn2).print();
                break;
            case 4:
                (cn1 / cn2).print();
                break;
            default:
                cout << "Error: You must enter a valid number for the desired operation (1-4)." << endl << endl;
                continue;
        }
        break;
    }

    cout << endl << "Thanks for using the calculator!" << endl << endl;
}