virtual functions in Objective C

Question

How to declare the virtual functions in Objective C.

virtual void A(int s);

How to declare the same in Objective C.

-(void)A:(int)s //normal declaration

All objective-C methods are virtual. Functions are construct from C language, those cannot be virtual. — Peter Štibraný, May 10 '11 at 14:41
possible duplicate of [What is the equivalent of a C++ pure-virtual function in Objective-C?](http://stackoverflow.com/questions/4374677/what-is-the-equivalent-of-a-c-pure-virtual-function-in-objective-c) — Brad Larson, May 10 '11 at 15:35

score 43 · Accepted Answer · edited Nov 26 '13 at 22:12

Objective-c does not support virtual functions, or to say that another way - all functions in obj-c classes are virtual as method calls are determined in run-time.

If your subclass overrides method from superclass and you reference subclass instance using pointer to superclass then subclass method will get called:

@interface A{
}
-(void) someMethod;
@end

@interface B : A{
}
-(void) someMethod;
@end

...
A* obj = [[B alloc] init];
[obj someMethod]; // method implementation from B will be called

virtual functions in Objective C

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