struktur data program link list

source code c++:
#include <cstdlib>
#include <iostream>

using namespace std;

class node{
      friend class list;
      friend ostream& operator<<(ostream&, const list&);
      public:
             node(char &t,node *p):info(t),berikut(p){}
      protected:
                char info;
                node *berikut;
      };
   

      class list{
            friend ostream& operator<<(ostream&,const list&);
            public:
                   list():kepala(0){}
                   ~list();
                   void sisip(char t);
                   int hapus(char& t);
                   int hapusbelakang(char& t);
                   int kosong(){return(kepala==0);}
                   void cetak();
            protected:
                      node *kepala;
                      node *nodebaru(char& t, node*p){
                              node *q=new node(t,p);return q;}
            };
   
         
 
      ostream& operator<<(ostream& out, const list& k){
               for(node* p=k.kepala;p;p=p->berikut)
               out<<p->info<<" ->";
               out<<"*\n";
               return out;
               }
            

      list::~list(){
      node* temp;
      for(node* p=kepala;p;){
          
            temp=p;
            p=p->berikut;
            delete temp;
            }
                       }
                    
      void list::sisip(char t){
           cout<<t<<" masuk list : ";
           node *p=nodebaru(t,kepala);
           kepala=p;
           }
        
      int list::hapus(char& t){
          if(kosong())return 0;//penghapusan gagal
          t=kepala->info;
          node* p=kepala;
          kepala=kepala->berikut;
          cout<<t<<endl;
          delete p;

          return 1;//penghapusan sukses
          }
       int list::hapusbelakang(char& t){
          if(kosong())return 0;//penghapusan gagal
          t=kepala->info;
          node*p=kepala;
          kepala=kepala->berikut;
          delete p;
          return 1;//penghapusan sukses
          } 
   
       
      void list::cetak(){
           for(node* p=kepala;p;p=p->berikut)
           cout<<p->info<<" ->";
           cout<<"*\n";
           }


int main(int argc, char *argv[])
{
    list x;
    char data;
    x.sisip('a');
    cout<<x;
    x.sisip('b');
    cout<<x;
    x.sisip('c');
    cout<<x;
    x.sisip('d');
    cout<<x;
    for(int i=0;i<5;i++){
            x.hapus(data);
            cout<<data<<" dihapus dari list: ";
            cout<<x;
            }
 
    system("PAUSE");
    return EXIT_SUCCESS;
}
hasil: