كلاسها و لينك ليستها

#include <iostream.h>
#include <conio.h>
#include <stdlib.h>
void table();
class ff{
     public:
               char name[21];
               char last_name[30];
               float num;
               ff *next;
} *first , *last;
int main()
{
int count = 0 ;
first = last = NULL;
table(); //calling table function
while(count != 100) //start of while
     {
            ff *avali = new ff;
                   if(!avali)
                           {
                                cout<<'\n'<<"not elocation unit";
                                getch();
                                exit(0);
                            }
           avali->next = NULL;
             if(first == NULL)
                    {
                         gotoxy(38,2); cout<<(count + 1);
                         first = last = avali;
                         gotoxy(1,4); cin>>avali->name;
                         gotoxy(10,4); cin>>avali->last_name;
                         gotoxy(28,4); cin>>avali->num;

                    }
              else
                         {
                             clrscr();
                             table();
                             gotoxy(38,2); cout<<(count + 1);
                             last -> next = avali;
                             last = avali;
                             gotoxy(1,4); cin>>avali->name;
                             gotoxy(10,4); cin>>avali->last_name;
                             gotoxy(28,4); cin>>avali->num;

                        }
        count++;
    }//end of while

ff *dovomi = new ff;
if(!dovomi) //if not free memory
      {
            cout<<'\n'<<"not elocation unit";
            getch();
            exit(0);
      }
            dovomi = first;
            table();
int m = 4;
while(dovomi) //start of while
            {
                        if(dovomi->num >= 17)
                                    {
                                                gotoxy(1,m); cout<<dovomi->name;
                                                gotoxy(10,m); cout<<dovomi->last_name;
                                                gotoxy(28,m); cout<<dovomi->num;
                                                m++;
                                    }
dovomi = dovomi -> next;
            if(m == 24)
                        {
                                    m == 4;
                                    cout<<"press any key to see the naxt page";
                                    getch();
                        }
            }//end of while
getch();
return 0;
}
/////////////////// void table started
void table()
{
            clrscr();
            cout<<"======================================\n";
            cout<<"name last_name nomreh\n";
            cout<<"======================================\n";
}