[C++] Virtual function in inheritance

This is a small inspection of virtual function in inheritance in C++.




#include <iostream>

using namespace std;

class BaseClass

{

public:

    BaseClass(){};

    ~BaseClass(){};

    virtual void testA()

    {

        cout << __FILE__ << "::" << __LINE__ << endl; // 2 called

        testB();

    }

    virtual void testB()

    {

        cout << __FILE__ << "::" << __LINE__ << endl; // without testB() in MyClass, it will be called.

    }

};

class MyClass: BaseClass

{

public:

    MyClass(){};

    ~MyClass(){};

    void testA()

    {

        cout << __FILE__ << "::" << __LINE__ << endl; // 1 called

        BaseClass::testA();

    }

    void testB()

    {

        cout << __FILE__ << "::" << __LINE__ << endl; // 3 called

    }

};

int main(int argc, char **argv)

{

    MyClass myA;

    myA.testA();

    return 0;

}

Result:

VirtualFunction.cpp::31

VirtualFunction.cpp::12

VirtualFunction.cpp::37