// complex.h - a class template for complex numbers
// from Nagler, Learning C++ (2004), start p. 358

#ifndef COMPLEX_H
#define COMPLEX_H

#include <iostream>
using namespace std;

template <typename T = double>  // default template argument
class Complex {

    // implicit inline friend for insertion operator
    friend ostream &operator<< (ostream &out, Complex const &arg) {
        return out << arg.real << " + " << arg.imag << 'i';
    }

public:
    Complex(T const &real = T(), T const &imag = T());
    Complex(Complex const &);
    ~Complex();
    static int getCount() { return counter; }

private:
    T real, imag;
    static int counter;
};

// implementation is here, not in a separate file (i.e., no complex.cpp)

template <typename T>  // basic, default, and converting ctor (p. 360)
Complex<T>::Complex(T const &real, T const &imag) : real(real), imag(imag) {
    ++counter;
}

template <typename T>  // copy ctor
Complex<T>::Complex(Complex const &o) : real(o.real), imag(o.imag) {
    ++counter;
}

template <typename T>  // dtor (added to example to manage the counter)
Complex<T>::~Complex() {
    --counter;
}

template <typename T>  // initialize static variable
int Complex<T>::counter = 0;

#endif