How to conditionally add a function to a class template?

Question

I have a Matrix class template as follows:

template
class Matrix
{
    T data[nrows][ncols];
public:
         


        

Answer 1

skypjack and max66 have both presented simple answers to the problem. This is just an alternate way of doing it, using simple inheritance, although it means the use of a child class for square matrices:

template
class Matrix
{
protected:
    T data[nrows][ncols];
public:
    T& operator ()(std::size_t i, std::size_t j)
    {
        return data[i][j];
    }
};

template
class SqMatrix : public Matrix 
{
public:
    setIdentity()
    {
        //Do whatever
    }
}