Pointers to arrays

[jmiller]

say i have a function that accepts a pointer like:
void SomeFunction(Obj *pObj);

and then i have an array of objects like:
Obj *myObjects = new Obj[10];

i know you can pass myObjects and it will be a pointer to the first element, but would it be possible to do this:

SomeFunction(&myObjects[5]) and thus just have pObj point to element 5 of myObjects?

thanks

[riis]

It will work, but this will give a pointer to the sixth object, since arrays are zero-based. I use it quite often for arrays which I don't want to work with sequentially.

[jmiller]

okay...
but let me ask you then, since myObjects[5] is a pointer, wouldn't passing the address of the pointer (&myObjects[5]) pass the address of the pointer itself, and not the address of the myObjects[5] variable?

[riis]

Originally posted by jmiller

Obj *myObjects = new Obj[10];

You've declared the array as an array of objects, not an array of pointers to objects. So myObjects[5] is an object, not a pointer. Hence &myObjects[5] will pass the address to the object itself.

If you want to declare myObjects as an array of pointers, then you should do something like this: Obj **myObjects = new Obj*[10]; Then you have to instantiate every object before you can use it: myObjects[0] = new Obj; , etc.
In the end you have to delete all myObjects[i] and delete[] myObjects itself.

[CornedBee]

Since myObjects[5] is just shorthand for *(myObjects+5) and &myObjects[5] therefore being &*(myObjects+5) you can write myObjects+5 to get a pointer to the 6th elements.

But the other syntax might be simpler to understand, it's a matter of preference.