Queue Pointer

/*
  File : queue_pointer.cpp
  Author : Jemmy R. Mongi
  Date : 18 September 2012
*/
#include <iostream>
#include <conio.h>
#include <stdio.h>
using namespace std;

struct node
{
    int data;
    node *link;
};
node *front = NULL;
node *rear = NULL;

void Insertion()
{
     node *temp;
     cout<< "Masukan nilai : ";
     cin>>temp->data;
     temp->link = NULL;
         //if(front == NULL)
         //{
              //front = temp;
              //rear = temp;
         //}
         //else
         //{
     rear->link = temp;
     temp = rear->link;
         //}   
}//end insertion
void Deletion()
{
     node *temp;
     if(front == NULL && rear == NULL)
     {
          system("cls");
          cout<<"Error, cannot delete, because Queue is empty\n";
     }
     else
     {
          temp = front;
          front = front->link;
          cout << "Number to be delete is : \n"<< temp->data;
          free(temp);
          if(front == NULL)
          {
               rear = NULL;
          }
     }
}//end deletion

void Display()
{
     node *temp;
     if(front == NULL && rear == NULL)
     {
          system("cls");
          cout<< "error cannot display, because Queue is Empty\n";
     }   
     else
     {
         temp = front;
         cout<< "elements in queue is : ";
         while(temp != NULL)   
         {
              cout<data;
         }
         temp = temp->link;
     }
}
//fungsi utama
int main()
{
    int pilih;
    while(pilih != 4)
    {
        cout<<"Queue Pointer\n";
        cout<<"1. Insert\n";
        cout<<"2. Delete\n";
        cout<<"3. Display\n";
        cout<<"4. Exit\n";
        cout<<"Masukan pilihan anda : ";
        cin>>pilih;
        switch(pilih)
        {
             case 1 :
                  Insertion();
                  break;
             case 2 :
                  Deletion();
                  break;
             case 3 :
                  Display();
                  break;
             case 4 :
                  exit(0);
                  break;
             default :
                     system("cls");
                     cout<<"maaf, pilihan tidak tersedia\n";
        }
    }
    system("pause");
    return 0;
}//end fungsi utama