Matrix class c++ implementation

Question

I am trying to implement a matrix class.

Class Definition

template <typename T>
class Matrix
{
private:
    int size;           //size of matrix
    T value;
    T ** M;
public:
    Matrix(int m = 2);

Class implementation

/* Matrix constructor */
template <typename T>
Matrix<T>::Matrix(int m) : size(m), value(0)
{
    M = new T*[size];
    for (int i = 0; i < size; i++)
    {
        M[i] = new T[size];
        for (int j = 0; j < size; j++)
        {
            M[i][j] = value;
        }
    }
}

This is how I create an object:

Matrix<int> A = Matrix<int>(3);

I keep getting this error:

Error 2 error LNK2019: unresolved external symbol "public: __thiscall Matrix::Matrix(int)" (??0?$Matrix@H@@QAE@H@Z) referenced in function _main

Any ideas what can be causing this?

You really should store the matrix as a flat array to take advantage of cache locality. — NathanOliver, Oct 26 '16 at 13:43
I will try the flat array, but I want to overload the * operator. Wouldn't it be harder that way? — Samu, Oct 26 '16 at 13:46
Linking template classes defined and implemented in different files is tricky. Have a look at this: http://www.codeproject.com/Articles/48575/How-to-define-a-template-class-in-a-h-file-and-imp — freakish, Oct 26 '16 at 13:46
You will need to define `T& operator[](size_t i, size_t j)` and `T operator[](size_t i, size_t j) const` anyway. You can write `Matrix operator*(const Matrix&rhs, const Matrix&lhs`) just in terms of that. — Martin Bonner supports Monica, Oct 26 '16 at 14:02
Also beware: Much better to declare `M` as `std::vector M;` - that way copy constructor, copy assignment operator (and their move counterparts) "just work". — Martin Bonner supports Monica, Oct 26 '16 at 14:03
For matrix classes, please search the internet for "c++ FAQ Matrix". There are some good issues discussed there. — Thomas Matthews, Oct 26 '16 at 15:53

Matrix class c++ implementation

0 Answers0