atp_lab_5_6_primer / priklad

#include <iostream>
using namespace std;
int main()
{
int A[6]={5,7,9,10,12,13};
int g1 = 4, g2 = 15, g3 = 11;

struct   c {
int n;
	c *prev;
	c *next;
};

c *begin = NULL;   
c *last = NULL;    
c *list = NULL;  
 
for (int i=0; i<6; i++)
	{ if (begin == NULL)
		{ 
		    last = new c;
			begin = last;
			last->n = A[i];
			last->prev = NULL;
			last->next = NULL;
			list = last; 
		}
	   else 
	   {    
	        last = new c;
			list->next = last;
			last->n = A[i];
			last->prev = list;
			last->next = NULL;
			list = last;
		}
	}


// додаемо елемент в голову списку
    list = new c;
    list->n = g1;
    list->prev = NULL;
	list->next = begin;
    begin->prev = list;
	begin = list;

// додаемо елемент у хвіст
    list = last;
    last = new c;
    list->next = last;
    last->n = g2;
    last->prev = list;
    last->next = NULL;

// вставляємо нове значення після 5 елементу
    int i=1;
    list = begin;
    c *nw = NULL;
	while (list) 
    { 
      i++;
	  list = list->next; 
      if (i==5)
      {
           nw = new c;
           nw->n = g3;
           nw->prev = list;
           nw->next = list->next;
           list->next = nw;
           list = list->next; 
           list = list->next; 
           list->prev = nw;
           break;
      }
    }



// виводимо список з голови
    list = begin;
    cout <<"Spisok = \n";
    while (list) 
    {
 	  cout<<list->n<<"\n";
	  list = list->next; 
    }

// виводимо список у зворотньому порядку
    list = last;
    cout <<"Spisok = \n";
    while (list) 
    {
 	  cout<<list->n<<"\n";
	  list = list->prev; 
    }
    delete list;
    delete last;
    delete begin;
    delete nw;
    return 0;
}

Spisok =
4
5
7
9
10
11
12
13
15
Spisok =
15
13
12
11
10
9
7
5
4