Accessing a class in a function using pointers

[OpiateDelusion]

This seems fairly easy, but I'm having a tough time accessing a class through pointers at any point in the code.

The project is an easy pet simulator, much like a tamigochi. I am trying to feed my pet through a function. I realize I can access the object from the source code and forget the function all together, but I would like to learn how this works before I go ahead.

How I think it works is that I need to pass the address of the pet object to the function, have the function make a pointer variable to that address, and have the code alter the variables in that object through the address.

In a case statement for user input, I have, under case 1 (Press 1 to feed pet)

void feedPet(beast *pet);

And here is the function itself.

void feedPet(beast newPet) {
    int * pNewPet = &newPet;
    cout << "You have fed your pet 10 pieces of food ";
    *pNewPet->eat();
    return;                                
}

and the functions prototype:

void feedPet(int &pointer);

If there is a phrase to explain what I am doing, I'd be willing to look it up. But at the moment, I have no clue what I should be looking up

[MacGyver]

*pNewPet->eat();

Lose the *.

[swoopy]

I would think all you'd need to do is this. Under case 1:

    feedPet(pet);

And the function:

void feedPet(beast &pet)
{
    pet.eat();
    cout << "You have fed your pet 10 pieces of food" << endl;
}

[dwks]

The "arrow" operator makes this

pNewPet->eat();

equivalent to

(*pNewPet).eat();

so there's no reason to add another *, making it

*(*pNewPet).eat();

since you're not using a pointer-to-a-pointer.

[OpiateDelusion]

I would think all you'd need to do is this. Under case 1:

    feedPet(pet);

And the function:

void feedPet(beast pet)
{
    pet.eat();
    cout << "You have fed your pet 10 pieces of food" << endl;
}

You could also pass the pet by reference if it contains several data members.

void feedPet(beast &pet)
{
    pet.eat();
    cout << "You have fed your pet 10 pieces of food" << endl;
}

It's still not looking at the address because "itsHunger" in the object is staying the same, even though it should be going down by 10 (eat() - 10 from itHunger.) It makes a new object each time it calls the function, and destroys it every time the function ends.

[swoopy]

Yeah sorry, it has to be a pointer or reference. Or you could make feedPet a member of the class, and do:

pet.feedPet();

[OpiateDelusion]

Yeah sorry, it has to be a pointer or reference. Or you could make feedPet a member of the class, and do:

pet.feedPet();

Thanks for the suggestion, I plan to use it.
I'd also like to learn how to reference an object from a function though, for later use of anything.

[swoopy]

>I'd also like to learn how to reference an object from a function though, for later use of anything.
Understood. In fact I guess the same idea would apply if you needed to change a std::string in a function, or any other object from the standard library.