Polymorphism?

[kedaman]

I'm a newbie here, when it comes to C++, but i know how to make functions that overloads each other. I've heard you can overload operators too for isntance

Cls1 Obj1;
Cls2 Obj2;

Obj1 = Obj2;
Obj1 = Obj1 + Obj2 / Obj1 * Obj1;
Obj1 += Obj2;

how do i achieve this?

[Vlatko]

Maybe you can use this:

Listing 10.8. Overloading operator++.

1:     // Listing 10.8
2:     // The Counter class
3:
4:     typedef unsigned short  USHORT;
5:     #include <iostream.h>
6:
7:     class Counter
8:     {
9:        public:
10:          Counter();
11:          ~Counter(){}
12:          USHORT GetItsVal()const { return itsVal; }
13:          void SetItsVal(USHORT x) {itsVal = x; }
14:          void Increment() { ++itsVal; }
15:          void operator++ () { ++itsVal; }
16:
17:       private:
18:          USHORT itsVal;
19:
20:    };
21:
22:    Counter::Counter():
23:    itsVal(0)
24:    {};
25:
26:    int main()
27:    {
28:       Counter i;
29:       cout << "The value of i is " << i.GetItsVal() << endl;
30:       i.Increment();
31:       cout << "The value of i is " << i.GetItsVal() << endl;
32:       ++i;
33:       cout << "The value of i is " << i.GetItsVal() << endl;
34:     return 0;
35: }
Output: The value of i is 0
The value of i is 1
The value of i is 2

[kedaman]

Thanks, i appreciate that much Can you explain how i would go doing these operations i mentioned?

15:          void operator++ () { ++itsVal; }

so if this works for Obj1++ then how do i get Obj1 = Obj1 + Obj2; to work?

[PsyVision]

#include <iostream.h>

class number
{
public:
int n;
number() {n = 1;}
number operator+ (number);
};

number number:perator+ (number N)
{
cout << "\noperator+() function is working ";
number T;
T.n = N + N.n;
return T;
}

void main()
{
number x,y,z;

Z = X.operator+(Y) //Explicit
cout << Z.n; //2

Z = X + Y; //Implicit
cout << Z.n; //2

Z = Z + X + Y; //Chain of calls
cout << Z.n; //4
}

Originally posted by kedaman
I'm a newbie here, when it comes to C++

Join the party kedaman.
For C++, we have to look to parksie, vlatko, and a few others .

I wish C++ coding was as easy as VB.
I'm still learning..still reading the tutorials at http:///www.cprogramming.com .

[kedaman]

Thanks, Psy, very nice of you helping me thanks for the tutorial Matt i'll have a look at it. Maybe i should add parksie to my ICQ list?

[Vlatko]

Here is a sample of how to overload the + operator.

1:     // Listing 10.14
2:     //Overload operator plus (+)
3:
4:     typedef unsigned short  USHORT;
5:     #include <iostream.h>
6:
7:     class Counter
8:     {
9:     public:
10:       Counter();
11:       Counter(USHORT initialValue);
12:       ~Counter(){}
13:       USHORT GetItsVal()const { return itsVal; }
14:       void SetItsVal(USHORT x) {itsVal = x; }
15:       Counter operator+ (const Counter &);
16:    private:
17:       USHORT itsVal;
18:    };
19:
20:    Counter::Counter(USHORT initialValue):
21:    itsVal(initialValue)
22:    {}
23:
24:    Counter::Counter():
25:    itsVal(0)
26:    {}
27:
28:    Counter Counter::operator+ (const Counter & rhs)
29:    {
30:       return Counter(itsVal + rhs.GetItsVal());
31:    }
32:
33:    int main()
34:    {
35:       Counter varOne(2), varTwo(4), varThree;
36:       varThree = varOne + varTwo;
37:       cout << "varOne: " << varOne.GetItsVal()<< endl;
38:       cout << "varTwo: " << varTwo.GetItsVal() << endl;
39:       cout << "varThree: " << varThree.GetItsVal() << endl;
40:
41:     return 0;
42: }

Output: varOne: 2
varTwo: 4
varThree: 6

[parksie]

Maybe i should add parksie to my ICQ list?

If you want. I'm 91747330

[kedaman]

Well good, now i have someone who i can ask anything about

[parksie]

Well...C++ related anyway

[kedaman]

Well, here's something related, about inheritance
Is it possible for a class to inherit two other classes?
I was thinking about letting a windowcomponent inhering both visualcomponent and a scriptcomponent.

[parksie]

Most things are possible. That of course depends on whether your brain explodes while debugging it .

class MyClass : public WindowClass, public ScriptClass {
    MyClass() { }
    virtual ~MyClass() { }

    int WindowClassFunction() { } // Overload from WindowClass

    int ScriptClassFunction() { } // Overload from ScriptClass
};

You also inherit any data members. Although I think you get an error (maybe a warning) if two classes you inherit from have two identical members.

[kedaman]

Thanks parksie, that was i was hoping for