Re: overloading the [] operator

Hello,

I've created a class to store 2 dimensional matrices, and I've been
trying to overload the [] operator, so access to the elements of the
matrix is easy. I have 3 private variables, _m, _row and _col which are
respectively the array to store the data in, the number of rows and the
number of columns. _m is of type T, and is size _row * _col * sizeof
(T).

I've managed to overload the subscript operator like this:
T & operator [] (int n)
{
     return (_m[n * _col]);
}

but I don't understand why you can't do:
T * operator [] (int n)
{
     return (&_m[n * _col]);
}

instead. The first one works fine, but with the second one when I try
something like m[0][0] = 100.0, m[0][0] comes up as being an invalid
lvalue.
Could someone help me out here?