C++ Operator Overloading: Customizing Syntax for User-Defined Types

Operator Overloading provides a clean, intuitive syntax for user-defined classes by extending the behavior of built-in C++ operators without altering their precedence or arity.

Example: Complex Number Addition & Stream Insertion (<<)

#include <iostream>

class Complex {
private:
    double real;
    double imag;

public:
    Complex(double r = 0, double i = 0) : real(r), imag(i) {}

    // Overloading '+' operator as a member function
    Complex operator+(const Complex& other) const {
        return Complex(real + other.real, imag + other.imag);
    }

    // Overloading '<<' stream operator as a friend function
    friend std::ostream& operator<<(std::ostream& out, const Complex& c) {
        out << c.real << " + " << c.imag << "i";
        return out;
    }
};

int main() {
    Complex c1(3.5, 2.5);
    Complex c2(1.5, 4.5);

    Complex c3 = c1 + c2; // Clean, mathematical syntax!
    std::cout << "Result: " << c3 << std::endl; // Output: 5 + 7i
    return 0;
}