Why Does Overloading the

Overloading the '<<' Operator for an ostream

When attempting to overload the '<<' operator for an ostream in C , you may encounter the error "error: 'std::ostream& Math::Matrix::operator<<(std::ostream&, const Math::Matrix&)' must take exactly one argument." This can be confusing, so here is a detailed explanation of the issue and a solution.

The overload of the operator is defined as 'std::ostream& operator<< (std::ostream& stream, const Matrix& matrix)'. As you can see, this function takes two arguments. However, the error message states that it should have only one. This is because, by default, the '<<' operator is a member function of the class being streamed into. Therefore, the first argument is implicitly the object being streamed. When overloading this operator, you need to explicitly specify the first argument as 'ostream&'.

The solution is to add 'void' as the first argument of the overload. This indicates that the operator is a friend function and not a member function.

Here is the corrected code:

namespace Math
{
    class Matrix
    {
    public:
        friend std::ostream&amp; operator<< (std::ostream&amp; stream, const Matrix&amp; matrix) {
            [...]
        }
    };
}

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