Calling derived class overriden function from parent. C++ -

i have parent class p, derived class d, , function show() in both of them. also, have array of p objects, , in array assigning objects derived p, d. , i'm calling show() function array. seems calls p empty function, not derived overriden function.

my code:

//parent.h      class p { public:     p(){ }     ~p(){ }      virtual void show(){ } };  //derived.h  #include "parent.h"  class d : public p { public:     d(){ }     ~d(){ }      void show(); };  //derived.cpp  #include "derived.h"  void d::show() {     std::cout<<"showing derived function\n"; } 

//main.cpp

#include "derived.h" #include <vector>  int main() {     vector<p> objectz;      for(int i=0; i<8; i++)     {         d derp;         objectz.insert(objectz.begin(), derp);     }      for(int i=0; i<8; i++)     {         objectz[i].show(); //call here !!     }      return 0; } 

this because didn't declare array array of p pointers. make sure array declared like:

p* elements[ n ]; 

here example code show polymorphism:

#include <iostream> #include <cstddef>  struct p {     virtual void func() { std::cout << "parent" << std::endl; } };  struct d : p {     void func() override { std::cout << "derived" << std::endl; } };  int main() {     const std::size_t n( 2 );      p* elements[ n ];      p parent;     d derived;      elements[ 0 ] = &parent;     elements[ 1 ] = &derived;      ( std::size_t i( 0 ); < n; ++i )         elements[ ]->func();      std::cout << "enter character exit: "; char c; std::cin >> c;     return 0; } 

using std::vector:

#include <iostream> #include <cstddef> #include <vector>  ... // same p , d definitions in previous example.  int main() {     std::vector<p*> elements;       elements.push_back( &p() ); // &p(): create instance of p , return address.     elements.push_back( &d() ); // &d(): create instance of d , return address.      ( std::vector<p*>::size_type i( 0 ), sz( elements.size() ); < sz; ++i )         elements[ ]->func();      std::cout << "enter character exit: "; char c; std::cin >> c;     return 0; }