Different constructor in template: one for string and one for anything else

Question

#include <iostream>
#include <string>
using namespace std;

template <class Type>
class Matrix
{
public:
    Type matrix[2][2];

        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 2; j++) {
                if (typeid(matrix[0][0]).name() == typeid(string).name()) {
                    matrix[i][j] = "0";
                }
                else {
                    matrix[i][j] = 0;     //this is where I get C2593
                }
            }
        }
    }
};

int main()
{
    Matrix<string> mString;
    Matrix<int> mInt;
    .
    .
    .
    return 0;
}

So, I'm having this matrix template and I want to initialize it with "0" if the type of the matrix is string. Else, I want to initialize with 0. I tried this thing here and I get an error C2593: 'operator =' is ambiguous. Is there anything I can do, or my approach is totally wrong?

Answer 1

It ultimately depends on how much of Matrix differs between int and string.

If all you're dealing with is the initial default value, the simplest solution is probably to outsource to a helper function:

template <class Type>
class Matrix
{
    Matrix() {
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 2; j++) {
                setDefault(matrix[i][j]);
            }
        }
    }

    // ...

    template <typename U>
    void setDefault(U& u) { u = 0; }

    void setDefault(std::string& u) { u = "0"; }
};

If you're doing something more complicated, then you probably want to explicitly specialize:

template <>
class Matrix<std::string> {
    // Matrix of strings
};