/**********************************************\
* Firtst laborators work at C++                *
* Dynamic structeres in memory /lists/         *
\**********************************************/

#include <stdio.h>
#include <stdlib.h>
#include <iostream.h>

struct TList
  {
  int data;
  struct TList *next,*prew;
  };

typedef struct TList ttlist;

ttlist *head, *work1, *work2, *work3;

//////////////////////////////////*\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
void print_list()
  {
  cout << "------------------------------\n";
  cout << "Now list is: \n";
  work1 = head;
  while (work1->next != NULL)
	 {
	 cout << "   digit: " << work1->data << "\n";
	 work1 = work1->next;
	 }
  cout << "   digit: " << work1->data << "\n";
  cout << "------------------------------\n";
  }

//////////////////////////////////*\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
void ins_member(int data)
  {
  work1 = head;
  if (work1->data > data)
    {
    work2 = (ttlist *)malloc (sizeof(ttlist));
    if (work2 == NULL)
       {
       cout << "Not enough memory to allocate buffer\nProgramm halted...\n";
       exit(1);
       }
    work2->prew = NULL;
    work2->next = head;
    head->prew = work2;
    head = work2;
    head->data = data;
    cout << "Data inserted succesfully!..\n\n";
    }
  else
    {
    while ((work1->data < data) && (work1->next != NULL))
      work1 = work1->next;
    if (work1->data > data)
      {
      work2 = work1->prew;
      work3 = (ttlist *)malloc (sizeof(ttlist));
      if (work3 == NULL)
         {
         cout << "Not enough memory to allocate buffer\nProgramm halted...\n";
         exit(1);
         }
      work3->data = data;
      work2->next = work3;
      work3->prew = work2;
      work1->prew = work3;
      work3->next = work1;
      cout << "Data inserted succesfully!..\n\n";
      }
    else
      {
      work2 = (ttlist *)malloc (sizeof(ttlist));
      work2->next=NULL;
      if (work2 == NULL)
         {
         cout << "Not enough memory to allocate buffer\nProgramm halted...\n";
         exit(1);
         }
      work2->data = data;
      work1->next = work2;
      work2->prew = work1;
      cout << "Data inserted succesfully!..\n\n";
      }
    }
  }

//////////////////////////////////*\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
int del_member(int data)
  {
  int err = -1;
  work1 = head;
  if (work1->data == data)
    {
    head = work1->next;
    head->prew = NULL;
    free(work1);
    err = 0;
    }
  else
    {
    while ((work1->data != data) && (work1->next != NULL))
      work1 = work1->next;
    if (work1->next != NULL)
      {
      work2 = work1->prew;
      work3 = work1->next;
      work2->next = work3;
      work3->prew = work2;
      free(work1);
      err = 0;
      }
    else if (work1->data == data)
           {
           work2 = work1->prew;
           work2->next = NULL;
           free(work1);
           err = 0;
           }
    }
  return(err);
  }

//////////////////////////////////*\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
void create_list()
  {
  head = (ttlist *)malloc (sizeof(ttlist));
  if (head == NULL)
    {
    cout << "Not enough memory to allocate buffer\nProgramm halted...\n";
    exit(1);
    }
  head->next = NULL;
  head->prew = NULL;
  }

//////////////////////////////////*\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
int cmpstr(char *str1, char *str2)
  {
  int i = 0;
  while ((str1[i] == str2[i]) && (str1[i] != 0) && (str2[i] != 0)) i++;
  if ((str1[i] == 0) && (str2[i] == 0)) return(1);
  else return(0);
  }

//////////////////////////////////*\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
//////////////////////////////////*\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
void main()
  {
  cout << "als Software /10 sep 1998/ \n";
  cout << "Copyrght by Alex L. Sterinovich\n";
  cout << "ÑÏÈÑÊÈ È ÄÈÍÀÌÈ×ÅÑÊÎÅ ÐÀÑÏÐÅÄÅËÅÍÈÅ ÏÀÌßÒÈ\n\n";
  cout << "To insert new member type command 'ins <data>',\n";
  cout << "to remove member type command     'del <data>',\n";
  cout << "to view list type command         'view',\n";
  cout << "to exit program type command      'exit'.\n\n";

  int i;
  create_list();
  cout << "Enter first data: ";
  cin >> i;
  head->data = i;
  cout << "List was created succesfully!..\n\n\n";

  int param;
  char command[4];

  while (!cmpstr(command,"exit"))
    {
    cout << "Enter command: ";
    cin >> command;
    if (cmpstr(command,"ins"))
      {
      cin >> param;
      ins_member(param);
      }
    else if (cmpstr(command,"del"))
           {
           cin >> param;
	   if (head->next != NULL)
             {
             if (del_member(param) == 0) cout << "Data removed...\n\n";
             else cout << "Can't remove data!..\nCan't find this data in list...\n\n";
             }
           else cout << "Can't remove data!..\nList must have at least one element!..\n\n";
           }
         else if (cmpstr(command,"view")) print_list();
              else if (!cmpstr(command,"exit"))
                     {
                     cout << "Invalid command!...\n\n";
                     cout << "To insert new member type command 'ins <data>',\n";
                     cout << "to remove member type command     'del <data>',\n";
                     cout << "to view list type command         'view',\n";
                     cout << "to exit program type command      'exit'.\n\n";
                     }
    }
  }