Overloading for derived class

Question

class A {
public:
void foo() {}
void foo(int x) {} //Why this function is not overloaded for a class B?
};

class B: public A {
public: void foo() {}
};

int main() {
B obj;
obj.foo(1); //Compiler error
return 0;
}

Answer 1

If you place a same-named function with a different signature (no int) in the derived class, all same-named functions of the base class get lost. If you still want to have the base class function available in B you will have to import with a using declaration just before the new version of f
using B::foo;
If you want to use polymorphism too, don't forget to put the virtual-keyword in the base class declaration of the function:
virtual void foo(int x);