Accessing public members of a class in another class

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Hi..

This is what I want to do :
1. Pass an object pointer of a class (say X) to the constructor of another class(say Y).

Now my question is :

Can I access the public members of class X in member functions of class Y ? If possible then I want to know how..as it's giving me some runtime failures.

Thankss in advance..!!

EDIT: Update to original question from the OP. [enhzflep]

This is what i wish to do :

C++

Class X
{
	public:
		int ver;
}

class Y
{
    y(X *obj)
    {
    }
	 
    void someMethod
    {
        cout<< obj.ver;
    }
}

void main()
{
  y obj1=new y();
  y.someMethod;
}

Can this be done.??

Posted 20-May-13 23:27pm

AsthaS

Updated 21-May-13 1:52am

enhzflep

v2

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Comments

Prasaad SJ 21-May-13 5:37am

Can't you access the public members of X as normal function arguments.
For example Y(X o){int i=o.i;}
You can use X as this way.

enhzflep 21-May-13 7:57am

Yes, this functionality can be achieved. Though you need to make a few changes.
1) You'll need ; characters after the closing brace for the class definitions.

2) You're passing a pointer to an object of class X, into the constructor for class Y. You then go on to try to print the 'ver' variable of this instance of X. Only problem is, you threw away the copy you got in the constructor....
Hint: Add a variable to hold the pointer given to you in the constructor. hintB: don't forget to change from . notation to -> notation when you use the pointer.

3 solutions

Solution 2

Yes, so long as class Y has a member variable of type Class X.

C++

#include <cstdio>

class class1
{
public:
    bool initialized;
    bool otherFuncUsed;
    class1()
    {
        initialized = true;
        otherFuncUsed = false;
    }
    void sampleFunc()
    {
        otherFuncUsed = true;
    }
};


class class2
{
public:
    class1 memberClass;
    class2()
    {
        printf("memberClass.otherFuncUsed = %d\n", memberClass.otherFuncUsed);
        memberClass.sampleFunc();
        printf("memberClass.otherFuncUsed = %d\n", memberClass.otherFuncUsed);
    }
};

int main()
{
    class2 sampleVar;
}

Posted 20-May-13 23:36pm

enhzflep

Solution 3

Content moved to original question.

Posted 20-May-13 23:50pm

AsthaS

Updated 21-May-13 1:58am

v2

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CPallini · Accepted Answer · 2013-05-20T23:32:00

Yes, you can.
You can access the public members of the object via the -> operator, of course.
I can't know why are you getting runtime failures, however I might suspect you are calling methods (or accessing data) of an invalid pointer (e.g. is the passed object still alive - has not be released - while you are accessing it?).

[Update]

C++

#include <iostream>
using namespace std;
class X
{
public:
    int ver;
    X(int v):ver(v){}
};

class Y
{
  X * px;
public:
  Y(X * pObj):px(pObj){}
  void showXVer(){ cout << "x version: " << px->ver << endl;}
};

int main()
{
    X x(42);
    Y y(&x);
    y.showXVer();
}

[/Update]