How to access derived class function from the base class object without using virtual function in c++?

Answer:

Using the typecasting we can call derive class object but not recommended because you have a virtual keyword. Let see an example program for the same,

#include<iostream>
using namespace std;
class A
{
public:
    A() {};
    ~A() {};
    void fun()
    {
        cout << "Base Class fun"<<endl;
    }
};
class B: public A
{
public:
    B() {};
    ~B() {};
    void fun()
    {
        cout << "Child Class fun"<<endl;
    }
};
int main()
{
    B bObj;
    A *aObj = &bObj;
    aObj->fun();
    return 0;
}

Output:

Base Class fun.

Now access derived class member using the typecasting but is not recommended,

#include<iostream>
using namespace std;
//Base class
class A
{
public:
    A() {};
    ~A() {};
    void fun()
    {
        cout << "Base Class fun"<<endl;
    }
};
//Child class
class B: public A
{
public:
    B() {};
    ~B() {};
    void fun()
    {
        cout << "Child Class fun"<<endl;
    }
};
int main()
{
    B bObj;
    A *aObj = &bObj;
    
    //Now Access child class but not recommended
    static_cast<B*>(aObj)->fun();
    
    return 0;
}

Output:

Child Class fun.