// Matrix.h

#ifndef MATRIX_H
#define MATRIX_H

#include <iostream>

using namespace std;

template<typename T>
class Matrix {
	private:
		size_t n, m, len;
		T *a;
	public:
		Matrix(size_t n, size_t m) : n(n), m(m), len(n * m), a(new T[len]) {
			for(size_t i(0); i < len; ++i)
				a[i] = 0;
		}
		~Matrix() {
			if(!a) return;
			delete[] a;
			a = nullptr;
		}
		T *operator [](size_t i) {
			return (i >= 0 && i < n && a) ? i * m + a : nullptr;
		}
		T const *operator [](size_t i) const {
			return (i >= 0 && i < n && a) ? i * m + a : nullptr;
		}
		T get_trace() const {
			T trace(0);
			if(!a) return trace;
			size_t c = n < m ? n : m;
			for(size_t i(0); i < c; ++i)
				trace += (*this)[i][i];
			return trace;
		}
		size_t get_n() const { return n; }
		size_t get_m() const { return m; }
		void init(T (*generator)()) {
			for(size_t i(0); i < len; ++i)
				a[i] = generator();
		}
};

template<typename T>
ostream &operator <<(ostream &out, Matrix<T> const &matrix) {
	size_t n(matrix.get_n()), m(matrix.get_m()), i(0), j(0);
	T const *row(matrix[i]);
	out << "[\r\n  [ " << row[j];
	for(++j; j < m; ++j)
		out << ", " << row[j];
	out << " ]";
	for(++i; i < n; ++i) {
		row = matrix[i];
		out << ",\r\n  [ " << row[j = 0];
		for(++j; j < m; ++j)
			out << ", " << row[j];
		out << " ]";
	}
	out << "\r\n]";
	return out;
}

#endif