overload function call operator

[jr.freester]

I've written a Matrix container class and overloaded the function call
operator to return values at a specified index.
Below is the member function

double operator()(int a , int b)
{
if((a < 1) || (b < 1) || ((a + 1) this->row) || ((b + 1) this-

>col))

{
cerr << "Invalid index for Matrix" <<endl;
}

return this->data[(a-1)*this->col + (b-1)];
}

It is invoked
int row, col;
double d;
Matrix M;
d = M(row,col);

My question is thus, can I accomplish the reverse task of assigning a
double d to a Matrix M at power row,col ie.
M(row,col) = d;

Justin

[Kai-Uwe Bux]

jr*********@gmail.com wrote:

I've written a Matrix container class and overloaded the function call
operator to return values at a specified index.
Below is the member function

double operator()(int a , int b)

Probably, it is not the best idea to allow signed arguments.

{
if((a < 1) || (b < 1) || ((a + 1) this->row) || ((b + 1) this-

>>col))

Probably, it would be better to go with the C convention to start indexing
at 0. This will get rid of many "-1" in the code, which are prone to error.

{
cerr << "Invalid index for Matrix" <<endl;

This should be an assert().

In an at()-method, it you would throw something.

}

return this->data[(a-1)*this->col + (b-1)];
}

It is invoked
int row, col;
double d;
Matrix M;
d = M(row,col);

My question is thus, can I accomplish the reverse task of assigning a
double d to a Matrix M at power row,col ie.
M(row,col) = d;

Yes, return a reference

double & operator()( size_type a, size_type b );
Best

Kai-Uwe Bux