passing an object as an argument to a function (by reference)

Hi,

how can I pass an object as an argument to a function. My knowledge of C++ is NULL but I do cope well with C so please accept my apologies if my question is rubbish. Basically here is my problem. Suppose there is a class call FooClass with some kind of contructor for two integers. In order to create an object I guess I would do something like

FooClass Foo(1,2);

Now I want to pass my Foo object by reference into a function called bar.

I would normarlly do something like
void
bar(FooClass *foo);

but I guess the above is completely wrong.... my compiler in any case is complaining (g++), as I think there is no constructor..... the thing is taht I don't want to create a new object but tell the bar function to expect a FooClass object.

Both google search and looking in the forum failed, mainly becayse I am not sure I am asking the question right....

Cheers.

To pass a reference to an object so that you can change it, you can do this:

Code:

---

void bar ( FooClass& foo );

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To pass a reference to an object so that you can't change it, you can do this:

Code:

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void bar ( const FooClass& foo );

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Can you post your exact code and the errors that you're getting if that doesn't work?

Cheers!

Quote:

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Originally Posted by Anubis

I think you might want to take a look at the "friend" keyword.

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no, that has nothing to do with the ops problem. why would you need the friend keyword here?

If the compiler is complaining about missing a constructor I'm inclined to believe it.

Ulysses :D post the definition of FooClass, and where you're calling bar().

Quote:

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Originally Posted by Slacker

To pass a reference to an object so that you can change it, you can do this:

Code:

---

void bar ( FooClass& foo );

---

---

This works just fine. Cheers.

I thought to pass by refrence you did something like this

Code:

---

#include <iostream>

using namespace std;

void test(int * get);
void undo(int * get);
void print(const int * get);

int main()
{
        int pass = 5;

        cout << pass << endl;

        test(&pass);

        cout << pass << endl;

        undo(&pass);
        print (&pass);
       
        return 0;
}
void print(const int * get)
{
        cout << *get << endl;
}
void undo( int * get)
{
  *get = *get / 25;
}

void test(int *get)
{
        *get = *get * *get * *get;
}

---

instead of

Code:

---

void test(int &get);

---

>> I thought to pass by refrence you did something like this
In C++, you can pass by reference using a pointer (like you did) or a reference (like Slacker showed). Using a reference is more common in C++, although there are different situations when each is better than the other.