Accessing a class in a function using pointers

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)

Code:

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void feedPet(beast *pet);

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And here is the function itself.

Code:

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

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and the functions prototype:

Code:

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void feedPet(int &pointer);

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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

Code:

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*pNewPet->eat();

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Lose the *.

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

Code:

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    feedPet(pet);

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And the function:

Code:

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

---

The "arrow" operator makes this

Code:

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pNewPet->eat();

---

equivalent to

Code:

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(*pNewPet).eat();

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

Code:

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*(*pNewPet).eat();

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

Quote:

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Originally Posted by swoopy

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

Code:

---

    feedPet(pet);

---

And the function:

Code:

---

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.

Code:

---

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.

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

Code:

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pet.feedPet();

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Quote:

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Originally Posted by swoopy

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

Code:

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pet.feedPet();

---

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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.

>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.