Operator Overloading

1class Complex {
2    double real, imag;
3
4public:
5    Complex(double r = 0, double i = 0) : real(r), imag(i) {}
6
7    // Binary + as member
8    Complex operator+(const Complex& other) const {
9        return Complex(real + other.real, imag + other.imag);
10    }
11
12    // Unary -
13    Complex operator-() const {
14        return Complex(-real, -imag);
15    }
16
17    // Comparison
18    bool operator==(const Complex& other) const {
19        return real == other.real && imag == other.imag;
20    }
21
22    // Subscript
23    double& operator[](int i) {
24        return i == 0 ? real : imag;
25    }
26
27    // Function call
28    double operator()() const {
29        return sqrt(real*real + imag*imag);
30    }
31
32    // Prefix ++
33    Complex& operator++() {
34        ++real;
35        return *this;
36    }
37
38    // Postfix ++
39    Complex operator++(int) {
40        Complex temp = *this;
41        ++real;
42        return temp;
43    }
44};
45
46Complex a(1, 2), b(3, 4);
47Complex c = a + b;    // (4, 6)
48Complex d = -a;       // (-1, -2)
49double mag = c();     // magnitude