Question

so I was writing some matrix classes in C++. So each matrix has a pointer to an array called entries, I am not sure if i’m doing this right but I am redeclaring the array in the sub class. (I’m no expert in C++)

Does this memory need to be free’d? Am I simply overwriting the pointer with the referenced array? Any help would be greatly appreciated.
Thanks

class Matrix {
protected:
    float* entries;
public:
    int rows;
    int cols;


    Matrix() {
    }
    ~Matrix() {
    }
};

class Matrix4x4 : public Matrix {
    protected:
        float entry[4][4];
    public:

    /* This will create an empty matrix */
    Matrix4x4() {
        //Define the size of the arrays
        rows = 4;
        cols = 4;
        this->empty();
    }
    ...
};

Answer 1

The code isn’t leaking memory and cannot possibly do so, since you never say new or malloc anywhere in your code*, nor do you call functions which do so in an unguarded fashion (i.e. outside RAII objects).

However, the code is also fairly useless and misguided (e.g. Matrix4x4::entry is hiding the vestigial Matrix::entry, and rows and columns seem to be somewhat redundant variables), and that can only be solved by sitting down with a good C++ book for a few hours.

_{*) or, as @Nicol Bolas has helpfully pointed out, make_shared together with a lost circular reference}