Question : class

why is the line derv.func(); fails with compiler error but it likes the line
derv.func_1(); I thought method overriding should work

class A
{
public:
       void func() { printf ("\n func base class \n" );}
       void func_1() { printf ("\n func_1 \n" );}
};

class B : public A
{
public:
      void func(int a) { }

};

int main (int argc, char *argv[])
{
B derv;
derv.func_1();
derv.func(); // compiler error says requires 1 argument.

return 0;
}

Answer : class

It's not just an override - it's a combination of an override and an overload that you do.

You've overridden the func function, including all of its overloads. You cannot call any of A's func methods from a B instance, since they're all hidden by overriding the func method.

This would work though :

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class A
{
  public:
        void func(int a) { printf ("\n func base class \n" );}
         void func_1() { printf ("\n func_1 \n" );}
};

class B : public A
{
public:
      void func(int a) {  }
 
};



// or this :

class A
{
  public:
        void func() { printf ("\n func base class \n" );}
         void func_1() { printf ("\n func_1 \n" );}
};

class B : public A
{
public:
      void func() { A::func(); }
      void func(int a) {  }
 
};