strange virtual function output

Hello everyone,

Why in the below code,

    pb->foo();

will output Final other than output Base? I have tested that the output is
Final.

My question is
1. pb points Final instance, and the foo in Final is not virtual method;
2. if function is virtual, we should invoke the foo based on the type of
instance pointed to, if not virtual, we should invoke the foo based on the
type which is the pionter type;
3. since foo in Final is not final, so the output should be invoking the foo
based on the type of pointer (which is Base), then the output should be Base?

[Code]
#include <iostream>

using namespace std;
 
class Base {
public:
    virtual int foo() {cout << "Base" << endl; return 0;}
};
 
class Derived: public Base
{
public:
    int foo() {cout << "Derived" << endl;return 0;}
};
 
class Final: public Derived{
public:
  int foo() {cout << "Final" << endl;return 0;}
};
 
int main()
{
    Final f;
    Base* pb = reinterpret_cast<Base*> (&f);
    pb->foo();
 
    return 0;
}
[/Code]

regards,
George