overloading the + operator

[meLlamanJefe]

Hello,

I have a short matrix class I am trying to set up for a small project. I would like to overload the + operator to simplify the code syntax. However I am running into a compilation issue that I am not familiar with. Here is a snippet of the relevant code:

// File Matrix.h
 
class Matrix
    {
    public:
        Matrix(int Rows);
        Matrix(int Rows, int Columns);
        ~Matrix();
 
         double &operator() (int Row, int Column)
        {
           if(Row < 0 || Column < 0 || Row > mRows || Column > mColumns)
           {
              // Out of range error
           }
 
           return(mData[(mColumns * Row) + Column]);
        }
 
        Matrix operator + (Matrix &B)
        {
           Matrix *A = this;
           if((A->GetRowCount() != B.GetRowCount()) ||
              (A->GetColCount() != B.GetColCount()))
           {
              // Matrices do not have the same dimensions
              return(*A);
           }
 
           Matrix C(A->GetRowCount(), A->GetColCount());
           for(int i = 0; i < A->GetRowCount(); ++i)
           {
              for(int j = 0; j < A->GetColCount(); ++j)
              {
                 C(i, j) = A(i, j) + B(i, j); // This is line 78 as referenced by the error below
              }
           }
           return(C);
        }
 
     private:
        int mRows;
        int mColumns;
        double *mData;
   }
 
 

And here is the error I am receiving from the compiler:

Matrix.h: In member function `FlightSim::MatrixFlightSim::Matrix::operator+(Fli ghtSim::Matrix&)':
Matrix.h:78: `A' cannot be used as a function
make: *** [Matrix.o] Error 1

I should mention that I am fairly new at C++ so I recognize my inexperience is sure to be a factor here.

Thanks!

[Ganon11]

A is a pointer to a Matrix, B is a Matrix, so it should be evident you need to treat them differently. You have been in the rest of the function, but here you write both A(i, j) and B(i, j). You may have to use A->(i, j) or some similar syntax, I'm not sure which.

[scruggsy]

A is a pointer to a Matrix, B is a Matrix, so it should be evident you need to treat them differently. You have been in the rest of the function, but here you write both A(i, j) and B(i, j). You may have to use A->(i, j) or some similar syntax, I'm not sure which.

You need to dereference A to get at the object it points to:

(*A)(i, j)

Your compiler will probably reject A->(i, j).
If you want to make your code more readable, I suggest:

Matrix A = *this;

[meLlamanJefe]

You need to dereference A to get at the object it points to:

(*A)(i, j)

Your compiler will probably reject A->(i, j).
If you want to make your code more readable, I suggest:

Matrix A = *this;

Thanks scruggsy. I certainly had tried A->(i, j) and as you mentioned the compiler did not like it either. Anyhow, I like the suggestion to dereference "this" so that's what I tried and it works like a charm.