#include <iostream>

class Complex
{
public:
    Complex(double real = 0.0, double imag = 0.0)
        : real{real}, imag{imag}
    {
    }

    Complex operator+(const Complex &other) const
    {
        return Complex{real + other.real, imag + other.imag};
    }

    Complex operator*(const Complex &other) const
    {
        return Complex{real * other.real - imag * other.imag,
                       real * other.imag + imag * other.real};
    }

    friend std::ostream &operator<<(std::ostream &os, const Complex &c)
    {
        os << c.real;
        if (c.imag >= 0) {
            os << "+";
        }
        os << c.imag << "i";
        return os;
    }

private:
    double real;
    double imag;
};

int main()
{
    Complex a{1.0, 2.0};
    Complex const b{3.0, 4.0};

    std::cout << "a = " << a << std::endl;
    std::cout << "b = " << b << std::endl;
    std::cout << "a + b = " << a + b << std::endl;
    std::cout << "a * b = " << a * b << std::endl;

    return 0;
}