structures

i am haveing 3 structures

1 struct1

2 struct2

3 struct 3

i want to send any on of them as an arguments for a function

how can i declare the function prototype


i want to send any 1 structure as arguments

Do you want to use a single function which to work with all of this 3 structures?

Quote:

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Originally Posted by ravirams

i want to send any on of them as an arguments for a function

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As I presume that there is something common in the nature of the structures, I would recommend using classes and inheritance.

Store common attributes in the base class, and send the base class as a parameter.

Code:

---

  class CBase
  {
  public:
  void Dance () {};
  ...
  };

---

and...

Code:

---

  class CClass1:public CBase
  {
  ...
  };
  class CClass2:public CBase
  {
  ...
  };
  class CClass3:public CBase
  {
  ...
  };

---

Have a Function:

Code:

---

  void MyFunc (CBase * pBase)
  {
  pBase->Dance ();
  ...
  }

---

Use it this way:

Code:

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void CreateObjects ()
  {
          CClass1 * pC1 = new CClass1 ();
          CClass1 * pC2 = new CClass1 ();
 
          // Same function, two dissimilar objects
          MyFunc (pC1);
          MyFunc (pC2);
 
          delete pC1;
          delete pC2;
  }

---

Note: I have not compiled the above.
A better sample that explains Inheritance and Polymorphism is here.

Quote:

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Originally Posted by ravirams

i am haveing 3 structures

1 struct1

2 struct2

3 struct 3

i want to send any on of them as an arguments for a function

how can i declare the function prototype

i want to send any 1 structure as arguments

---

You can make them inherit from a base structure so you can treat them polymorphically, in which case the function prototype will use the base structure, or provide an overloaded method each taking a different structure.

If Virtual Functionalities and Polymorphism have to be used, using a class is best recommended.
Reason:

Quote:

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Originally Posted by MSDN

In C++, a structure is the same as a class except that its members are public by default.

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Perhaps, it's a good time to move to classes. ;)

Quote:

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Originally Posted by Siddhartha

Perhaps, it's a good time to move to classes. ;)

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As that note says, the only difference between structs and classes in C++ are accessors, but I'm not advocating the usage of structs over classes. ;)

PS: I've already taken part in a long debate in the C# forum about structs and classes in C# I'm not going to do it again, so soon... :D

Quote:

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Originally Posted by cilu

I'm not advocating the usage of structs over classes. ;)

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I did not quote you - I was addressing the OP - 'coz he uses struct. ;)

Quote:

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Originally Posted by Siddhartha

If Virtual Functionalities and Polymorphism have to be used, using a class is best recommended.

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Why would that be?

In C++ there are only two differences between a class and a structure:

• By default, the members of a class are private while the members of a structure are public
• By default, a struct inherits publicly while a class inherits privately

In other words...everything that a class can do, a structure can as well... ;)

Quote:

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Originally Posted by Andreas Masur

Why would that be?

In C++ there are only two differences between a class and a structure:

• By default, the members of a class are private while the members of a structure are public
• By default, a struct inherits publicly while a class inherits privately

In other words...everything that a class can do, a structure can as well... ;)

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The reason is exactly what you mentioned - in C++ (today) a struct is given all the functionalities of a class - baring defaults.

Given this situation, perhaps, it is best to call a struct being used as a class, a class.

Quote:

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Originally Posted by Siddhartha

The reason is exactly what you mentioned - in C++ (today) a struct is given all the functionalities of a class - baring defaults.

Given this situation, perhaps, it is best to call a struct being used as a class, a class.

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Ahh...okay...I thought I missed some technical reason...however, I still prefer structs over classes if I simply need to hold data...sometimes it is not worth adding the overhead of accessors....granted they will be inlined anyway...

Quote:

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Originally Posted by Andreas Masur

Ahh...okay...I thought I missed some technical reason...however, I still prefer structs over classes if I simply need to hold data...

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Me too, if holding data is all that it needs to do. :D

Quote:

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Originally Posted by Andreas Masur

sometimes it is not worth adding the overhead of accessors....granted they will be inlined anyway...

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I agree with you there - are accessor methods inlined as a result of optimization (like the rest of code), or does the compiler intelligently detect them as accessors-methods, and inline them intentionally?
Not sure if I am clear in my query...

They are inlined if you declare them as inline (though you cannot be sure that a function declared as inline will be actually inlined by the compiler), or if you implement them in the class declaration:

Code:

---

class foo
{
  int data;
public:
  // this is an inline function
  int GetData() const
  {
    return data;
  }
};

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Guys, sorry for my ignorance, but i think accessor functions re those which re used to access the private data members right (pls correct me if iam wrong)?

Ciao :)

Quote:

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Originally Posted by logan

Guys, sorry for my ignorance, but i think accessor functions re those which re used to access the private data members right (pls correct me if iam wrong)?

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Yes, you are right. :thumb:

Presumably: if they are small enough, they become inline.