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Old March 23rd, 2020, 02:55 AM
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Default Runtime Polymorphism in C++

Hello Everyone, I am confused about the concept of Runtime Polymorphism in C++. I have faced one interview and the interviewer asked me this question where I was not given the answer. I have checked in google with code example but I didn't get it. Can anyone know about it and suggest me some more questions which are very useful to me for my upcoming interviews? I have added one code example of runtime polymorphism, is it right?

#include
using namespace std;
class Base {
public:
virtual void show() { cout<<" In Base \n"; }
};
class Derived: public Base {
public:
void show() { cout<<"In Derived \n"; }
};

int main(void) {
Base *bp = new Derived;
bp->show(); // <- Runtime Polymorphism in Action
return 0;
}
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Old April 3rd, 2020, 04:38 AM
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Default

In the aforementioned program bp is a pointer of type Base. A call to bp->show() calls show() function of the Derived class. This is because bp points to an object of the Derived class.

Things essential to writing a virtual function in C++ are:

1. A base class
2. A derived class
3. A function with the same name in both the classes i.e. the base class and the 4. derived class
5. A pointer or reference of base class type that points or refers, respectively to an object of the derived class

Now i have clear about virtual functions in C++, thanks to this post. It's very useful and helpful.
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