How to properly overload the << operator for an ostream?

Question

I am writing a small matrix library in C++ for matrix operations. However my compiler complains, where before it did not. This code was left on a shelf for 6 months and in b

Answer 1

To add to Mehrdad answer ,

namespace Math
{
    class Matrix
    {
       public:

       [...]


    }   
    std::ostream& operator<< (std::ostream& stream, const Math::Matrix& matrix);
}

In your implementation

std::ostream& operator<<(std::ostream& stream, 
                     const Math::Matrix& matrix) {
    matrix.print(stream); //assuming you define print for matrix 
    return stream;
 }