bcc3.1 list "template"

LIST.H

#ifndef __LIST_H__
#define __LIST_H__
#include <iostream.h>

#define makeNormalList(type) makeList(List_##type, type)
#define makePointerList(t) makeList(List_pointer##t, t *)


#define makeList(name, type)\
class name {\
public: \
    type data;\
    name * next;\
    name * last();\
    name (type d):data(d), next(NULL){}\
    name (type d, name * n):data(d),next(n){}\
    static void insert_front(name ** l, type data);\
    static void insert_back(name ** l, type data);\
    static name * removeItem(name ** l, name * before, name * elem);\
    void printList();\
};\
name * name :: last()\
{\
    name * l = this;\
    while (l && l->next)\
        l=l->next;\
    return l;\
}\
void name :: insert_front(name** l, type data)\
{\
    name * t = new name (data);\
    t->next = *l;\
    *l = t;\
}\
void name :: insert_back(name** l, type data)\
{\
    name * t = new name (data);\
    name * last = (*l)->last();\
    if (!last)\
        *l = t;\
    else\
        last->next = t;\
}\
name * name :: removeItem(name ** l, name * before, name * elem)\
{\
    if (!elem) return NULL;\
    name * sled = elem -> next;\
    if (!before)\
        *l = sled, delete elem;\
    else \
        before -> next = sled, delete elem;\
    return sled;\
}\
void name :: printList()\
{\
    name * l = this;\
    while (l)\
        cout<<l->data<<endl, l = l->next;\
}

#endif

Usage:

#include <iostream.h>
#include "LIST.H"

makeList(List_int, int) // same as makeNormalList(int)
makeList(List_pointerint, int *) // first parameter is suffix name for class, second is data type stored in it

List_pointerint * l1;
List_int * list;

int main(int argc, char * argv[])
{
  List_int::insert_front(&list,0);
  List_int::insert_back(&list,1);
  List_int::insert_back(&list,2);
  List_int::insert_back(&list,3);
  List_int::insert_back(&list,4);

  list->printList(); // prints 0,1,2,3,4 
  cout<<"##########"<<endl;

  List_int * current = list;
  List_int * previous = NULL;
  while (current->next) // loop to last element while preserving previous element
      previous = current, current = current->next;
  current = List_int::removeItem(&list, previous, current); // removeItem returns pointer to next element in list (since we are removing last element -> NULL)
  list->printList(); // prints 0,1,2,3

  for (current = list, previous = NULL; current; previous = current, current = current->next, delete previous); //clear list

  return 0;
}