dynamical binding or switch/case?

Posted by kingkai on Stack Overflow See other posts from Stack Overflow or by kingkai
Published on 2010-04-21T08:31:02Z Indexed on 2010/04/21 8:33 UTC
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A scene like this:
I've different of objects do the similar operation as respective func() implements.
There're 2 kinds of solution for func_manager() to call func() according to different objects

Solution 1: Use virtual function character specified in c++. func_manager works differently accroding to different object point pass in.

class Object{
  virtual void func() = 0;
}
class Object_A : public Object{
  void func() {};
}
class Object_B : public Object{
  void func() {};
}
void func_manager(Object* a)
{
   a->func();
}

Solution 2: Use plain switch/case. func_manager works differently accroding to different type pass in

typedef _type_t
{
  TYPE_A,
  TYPE_B
}type_t;

void func_by_a()
{
// do as func() in Object_A
}
void func_by_b()
{
// do as func() in Object_A
}
void func_manager(type_t type)
{
    switch(type){
        case TYPE_A:
            func_by_a();
            break;
        case TYPE_B:
            func_by_b();
        default:
            break;
    }
}

My Question are 2:
1. at the view point of DESIGN PATTERN, which one is better?
2. at the view point of RUNTIME EFFCIENCE, which one is better? Especailly as the kinds of Object increases, may be up to 10-15 total, which one's overhead oversteps the other? I don't know how switch/case implements innerly, just a bunch of if/else?

Thanks very much!

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