[C++] overloading [] on pointers
 

I have a vector and matrix class and i'm impementing an iterative method to solve a IBVP. In this class I have overloaded the [] to work on the class just fine.

However, now I have ran into a problem where I don't want to be passing around whole objects and copy them around I want to do it with pointers to the objects. However I still want to be able to use my array notation.


So currently I use syntax like the following:

Vector X(16);
Vector *X0=&X;

...

(*X0)[0]=.....

I'd like to be able to just use

X0[0]=....


So I tried adding a non-member function like the following

double& operator[] (Vector* V, unsigned i)
{
return (*V)[i];
}

however the compiler gives me an error saying [] must be a non static member.

I can't see how to overload this operator as a static member. Anyone have any suggestions?

Just use references if you can -
Vector & X0 = X;

Thanks that worked great. I never actually thought about creating refrences like that.

If I have X0 and X1 which are refrences to 2 different vectors swap(X0,X1) will only swap the refrence right? I want to make sure it behaves like a full deep copy without actually performing a deep copy.

Also does anyone know if there is a way to overload [] operators not in a class? I think it would be really cool to make a class that behaved exactly like an array but with different symantics. Like array bounds checking, general bounds checking, maybe 1 based arrays instead of 2 based. It could be useful to develop using a class like this and then for a release move to the normal arrays.

You can only overload [] by member functions of a class. Same goes for = () ->

Not sure if this is what you mean WRT a class behaving like an array with different semantics...Use the STL containers.

Use iterators to navigate over STL containers like the vector, and for element access use at(). You can try/catch an out of range error on the at() command as it does a range check. If you want you can still use the operator[], but you have to make sure you perform the range check. Iterators have the begin()/end() functions that should be used.