Question

I have a custom Vector class that contains an x, y, and z. These are stored in an int array called data. So basically data[0] = x, data[1] = y, and data[2] = z. Simple enough.

I am tasked with writing a function that allows the following:

vector[0] = 2.0f;

Which should make the x value of the vector be 2.0. I’ve already overloaded the [ ] operator so that it returns a float (it’s essentially a getter method – ex:

cout << vector[0];

Would print whatever the x value of vector is.)

I’m confused as to how I can assign the float to the x, y or z. I think I need to overload an operator (perhaps the =), but I am not sure. Am I thinking about this the right way?

Answer 1

To do this, you need to provide a version of operator[] that returns a reference to the member that you want to be assignable to. For example:

class vector {
public:
    float& operator[](int pos) {
        return data[pos];
    }
    //You should also provide a const qualified overload
    //so that operator[] can be called on a const vector
    float operator[](int pos) const {
        return data[pos];
    }
private:
    float data[3];
};