#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
 
template<typename T>
struct Matrix{
    Matrix(size_t width, size_t height):
        _width(width),
        _height(height),
        _data(width*height){}
 
    auto width() const{ return _width; }
 
    auto height() const{ return _height; }
 
    auto *operator[](size_t idx){ return _data.data() + (idx * _height); }
    const auto *operator[](size_t idx) const{ return _data.data() + (idx * _height); }
 
    auto begin(){ return ::begin(_data); }
    auto begin() const{ return ::begin(_data); }
 
    auto end(){ return ::end(_data); }
    auto end() const{ return ::end(_data); }
private:
    size_t _width, _height;
    std::vector<T> _data;
};
 
int main(){
	Matrix<int> m(15, 15);
	iota(begin(m), end(m), 0);
 
	for(size_t y = 0; y < m.height(); ++y){
		for(size_t x = 0; x < m.width(); ++x){
			cout << m[y][x] << ' ';
		}
		cout << '\n';
	}
}

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