How to override a function in derived class when Inheriting - c++

Question

I have two classes - Mother(Base) and Daughter(Derived). I am inheriting a function from Mother class and trying to override in Daughter class. It looks like that it overrides, but my confusion is, even though I don't inherit Mother class, the function still works, so how am I inheriting/overriding it? I am very confused as if I'm really inheriting/overriding anything. Please note in the Derived class that I am not inheriting : public Mother
Thanks for the help, as always!!!
This is my code
Mother.hpp
#ifndef Mother_hpp
#define Mother_hpp
#include <iostream>
#include <string>
class Mother
{
public:
Mother();
void sayName();
};
Mother.cpp
#include <iostream>
#include <string>
#include "Mother.hpp"
#include "Daughter.hpp"
using namespace std;
Mother::Mother(){}
void Mother::sayName(){
cout<<"I am Sandy" <<endl;
}
Daughter.hpp
#ifndef Daughter_hpp
#define Daughter_hpp
#include <iostream>
#include "Mother.hpp"
class Daughter : public Mother
{
public:
Daughter();
void sayName();
};
Daughter.cpp
#include <iostream>
#include "Mother.hpp"
#include "Daughter.hpp"
using namespace std;
Daughter::Daughter() : Mother(){}
void Daughter::sayName(){
cout << "my name is sarah" <<endl;
}
Main.cpp
#include <iostream>
#include "Mother.hpp"
#include "Daughter.hpp"
using namespace std;
int main(int argc, const char * argv[]) {
Mother mom;
mom.sayName();
Daughter d;
d.sayName();
return 0;
}

Answer 1

but my confusion is, even though I don't inherit Mother class, the function still works, so how am I inheriting/overriding it? I am very confused as if I'm really inheriting/overriding anything.
you don't really override sayName() of your Mother class because (as you said) Daughter class doesn't inherit it in the first place. That is, you need to inherit a class first in order to be able to override its virtual functions.
your second call to sayName() works because it's a call to a member function of Daughter class, which is totally independent from Mother class. Note that, just having multiple independent classes whose member functions share the same signature is not overriding
side note: you shouldn't include Daughter.hpp in Mother.cpp, whether you plan to inherit Mother in Daughter, or not.