Const operator overloading problems in C++
- by steigers
Hello everybody,
I'm having trouble with overloading operator() with a const version:
#include <iostream>
#include <vector>
using namespace std;
class Matrix {
public:
Matrix(int m, int n) {
vector<double> tmp(m, 0.0);
data.resize(n, tmp);
}
~Matrix() { }
const double & operator()(int ii, int jj) const {
cout << " - const-version was called - ";
return data[ii][jj];
}
double & operator()(int ii, int jj) {
cout << " - NONconst-version was called - ";
if (ii!=1) {
throw "Error: you may only alter the first row of the matrix.";
}
return data[ii][jj];
}
protected:
vector< vector<double> > data;
};
int main() {
try {
Matrix A(10,10);
A(1,1) = 8.8;
cout << "A(1,1)=" << A(1,1) << endl;
cout << "A(2,2)=" << A(2,2) << endl;
double tmp = A(3,3);
} catch (const char* c) { cout << c << endl; }
}
This gives me the following output:
NONconst-version was called - - NONconst-version was called - A(1,1)=8.8
NONconst-version was called - Error: you may only alter the first row of the matrix.
How can I achieve that C++ call the const-version of operator()? I am using GCC 4.4.0.
Thanks for your help!
Sebastian
