йоу-йоу

#include "stdafx.h"
#include<iostream>
using namespace std;
struct item
{     int data;
      item *next;
 };
item *head, *tail;
bool isnull(void)
{      return (head == NULL);
 }
void delete()
{     if(isnull())
            cout<<"Пустота"<<endl;
      else
      {     item *p = head;
              head = head -> next;
              delete p;
       }
}
 void add(int x)
{      item *p = new item;
        p -> data = x;  p -> next = NULL;
        item *v = new item;
        item *p1 = new item;
        item *p2 = new item;
         int i = 0;
         if (isnull()) head = tail = p;
         else
		{      p2 = head;  p1 = head;
        while(p1 != NULL)
			 {       if (i == 1)
				   {      if(x <= p1 -> data )
                              {       v -> data = x; v -> next = p1;
                                      p2 -> next = v;
                                      return;
                              }
                          p2 = p2 -> next;                     }
                   else
                   {      if(x <= p1 -> data )
                           {        v -> data = x;  v -> next = p1;
                                     head = v;
                                     return;
                            }
                   }
                      p1 = p1 -> next;   i = 1;
			 }
if(p1 == NULL) {    tail -> next = p;     tail = p;   }
       }
 }


void out()
{     item *p = new item;
	  cout <<endl;
       if(isnull())
            cout<<"Пустота"<<endl;
       else
       {    cout<<"Очередь = ";
             p = head;
			 int q=0;
             while(!isnull())
     {
       if (p != NULL)
{cout << endl; cout<< q <<" элемент = "<<p->data<<";"; p = p -> next;  q++;  }
     }
	   cout <<endl;
	   cout <<endl;
       }
}
void delall() //Очистка очереди
{    while(!isnull())
      delete();
}
int main()
{        setlocale (LC_CTYPE, "Russian");
int i = 1, num = 1, z;
head = NULL;
tail = NULL;
while (num != 0)
  {cout<<" ------------------------------------"<<endl;
   cout<<"|---  1 - добавить элемент -----------|"<<endl;
   cout<<"|---  2 - извлечь элемент с начала ---|"<<endl;
   cout<<"|---  3 - вывести элемент ------------|"<<endl;
   cout<<"|---  4 - очистить очередь -----------|"<<endl;
   cout<<"|---  0 - выход ----------------------|"<<endl;
   cout<<" ------------------------------------"<<endl;
   cout << endl;
   cout<<"Выберите действие  ";
   cin>>num;
switch(num)
 {
 case 1: cout<<"Введите элемент:  ";
              cin>>z;  add(z);
              break;
 case 2: delete(); break;
 case 3: out(); break;
 case 4: delall(); break;
                      }
           }
                     return 0;
}