我可以调用从 main(） 覆盖的虚拟函数吗?

我知道这个

// C++ program for function overriding 
#include <bits/stdc++.h> 
using namespace std; 
class base 
{ 
public: 
virtual void print () 
{ cout<< "print base class" <<endl; } 
void show () 
{ cout<< "show base class" <<endl; } 
}; 
class derived:public base 
{ 
public: 
void print () //print () is already virtual function in derived class, we could also declared as virtual void print () explicitly 
{ cout<< "print derived class" <<endl; } 
void show () 
{ cout<< "show derived class" <<endl; } 
}; 
//main function 
int main()  
{ 
base *bptr; 
derived d; 
bptr = &d; 
//virtual function, binded at runtime (Runtime polymorphism) 
bptr->print();  
// Non-virtual function, binded at compile time 
bptr->show();  
return 0; 
} 

我可以打印

print derived class
show base class
show derived class

我可以打印吗

print base class

使用派生类的对象d，只需更改main()而不创建另一个对象？ 如果是，如何？