How to use unique pointers to create matrix? - c++11

Question

I have to create a matrix using unique poiters that permit operations: Matrix a,b; Matrix c(b) and Matrix d=a;
So far I did the simple implementing of a matrix
class Matrix
{
public:vector<vector<int>> data;
Matrix() {}
Matrix(vector<vector<int>> matrix)
{
this->data=matrix;
}
Matrix (const Matrix& m2)
{
this->data=m2.data;
}
Matrix& operator= (const Matrix &m2)
{
this->data = m2.data;
return *this;
}
}
It's first time for me facing unique_ptr vectors, I found a plenty of informations about unique_ptr vectors creating arrays, but not much for matrix, it's so unclear.
How can I use unique_ptr vectors(I must use them) instread of simple vector?
Any help is welcome, thank you!

Answer 1

Try this for init matrix only with std::unique_ptr [1]:
const int rowCount = 3;
const int clmnCount = 6;
std::unique_ptr<std::unique_ptr<int[]>[]> matrix(new std::unique_ptr<int[]>[rowCount]());
// or
// auto matrix = new std::unique_ptr<int[]>[rowCount]();
for (int i = 0; i < rowCount; i++)
matrix[i] = std::make_unique<int[]>(clmnCount);
Example of use [1]:
#include <iostream>
#include <iomanip>
#include <memory>
int main() {
const int rowCount = 3;
const int clmnCount = 6;
std::unique_ptr<std::unique_ptr<int[]>[]> matrix(new std::unique_ptr<int[]>[rowCount]());
for (int i = 0; i < rowCount; i++)
{
matrix[i] = std::make_unique<int[]>(clmnCount);
for (int j = 0; j < clmnCount; j++) {
matrix[i][j] = j;
std::cout << std::setw(3) << matrix[i][j];
}
std::cout << std::endl;
}
}
Or if u want use std::vector of std::unique_ptr try this [2]:
const int rowCount = 3;
const int clmnCount = 6;
std::vector<std::unique_ptr<int[]>> matrix;
for (int i = 0; i < rowCount; i++)
matrix.push_back(std::make_unique<int[]>(clmnCount));
Example of use [2]:
#include <iostream>
#include <iomanip>
#include <memory>
#include <vector>
int main() {
const int rowCount = 3;
const int clmnCount = 6;
std::vector<std::unique_ptr<int[]>> matrix;
for (int i = 0; i < rowCount; i++)
{
matrix.push_back(std::make_unique<int[]>(clmnCount));
for (int j = 0; j < clmnCount; j++) {
matrix[i][j] = j;
std::cout << std::setw(3) << matrix[i][j];
}
std::cout << std::endl;
}
}