Operator overloading with dynamic allocated matrix - c++

Question

I'm writting some code for teaching myself C++.
Does the following code:
#include <iostream>
using namespace std;
class Matrix
{
int m, n;
public:
float** value;
Matrix(int m, int n)
{
value = new float*[m];
for (int i = 0; i < m; ++i)
value[i] = new float[n];
this->m = m; this->n = n;
}
~Matrix()
{
for (int i = 0; i < m; ++i)
delete[] value[i];
delete[] value;
}
Matrix(const Matrix& A)
{
m = A.getLength();
n = A.getWidth();
value = new float*[m];
for (int i = 0; i < m; ++i)
value[i] = new float[n];
for (int i = 0; i < m; ++i)
for (int j = 0; j < n; ++j)
value[i][j] = A.value[i][j];
}
int getLength(void) const
{
return m;
}
int getWidth(void) const
{
return n;
}
void print() const
{
for (int i = 0; i < m; ++i)
{
for (int j = 0; j < n; ++j)
cout << value[i][j] << "\t";
cout << endl;
}
}
Matrix operator + (const Matrix& B)
{
if (m != B.getLength() || n != B.getWidth())
return Matrix(0, 0);
Matrix C = Matrix(m, n);
cout << value << endl;
for (int i = 0; i < m; ++i)
for (int j = 0; j < n; ++j)
C.value[i][j] = value[i][j] + B.value[i][j];
return C;
}
void operator = (const Matrix& A)
{
m = A.getLength();
n = A.getWidth();
value = new float*[m];
for (int i = 0; i < m; ++i)
value[i] = new float[n];
for (int i = 0; i < m; ++i)
for (int j = 0; j < n; ++j)
value[i][j] = A.value[i][j];
}
};
int main()
{
Matrix A = Matrix(3, 3);
A.value[0][0] = 1; A.value[0][1] = 2; A.value[0][2] = 3;
A.value[1][0] = 4; A.value[1][1] = 5; A.value[1][2] = 6;
A.value[2][0] = 7; A.value[2][1] = 8; A.value[2][2] = 9;
Matrix B = Matrix (3, 3);
B.value[0][0] = 1; B.value[0][1] = 2; B.value[0][2] = 3;
B.value[1][0] = 4; B.value[1][1] = 5; B.value[1][2] = 6;
B.value[2][0] = 7; B.value[2][1] = 8; B.value[2][2] = 9;
Matrix C = A + B;
cout << C.value << endl;
C.print();
return 0;
}
Generate a memory leak at the part "Matrix C = A + B"? I don't know if the returned matrix is destroyed after the association is done. If yes, is there a way to fix it?

Answer 1

In statement
Matrix C = A + B;
there is no leak.
Though in your code the copy assignment operator is not used nevertheless your copy assignment operator does not free the memory previously allocated to the matrix of an object.
The copy assignment operator differs from the copy constructor in that that the object is already created and has an allocated matrix. Also you have to check whether there is the self assignment.
Also it should be declared as
Matrix & operator = (const Matrix& A)
As for operator + then it should be declared as
Matrix operator + (const Matrix& B) const;
or as
const Matrix operator + (const Matrix& B) const;