help with a snippet

[yamokosk]

Alright, i have starred at this for sometime, and while i could try every combination of const modifier, I would rather get an explanation why this won't go. I still get hung up on const stuff...

Matrix& Matrix::operator = (const Matrix& m) {
	if (*this == m) {
		for (int r = 0; r < rows(); r++) {
			for (int c = 0; c < cols(); c++) {
				(*this)(r,c) = m(r,c);
			}
		}
		return *this;
	} else {
		throw std::invalid_argument("Error! Matricies must be equal for assignment.");
	}
}

I get the following error on compile:

error C2662: 'cols' : cannot convert 'this' pointer from 'const class Matrix' to 'class Matrix &'
Conversion loses qualifiers
error C2662: 'rows' : cannot convert 'this' pointer from 'const class Matrix' to 'class Matrix &'
Conversion loses qualifiers

Thanks in advance!