C Linked List

Created: March 21, 2017
Author: Matt Mumau
Licensed: MIT License (see included LICENSE file)
Repository: https://github.com/mpmumau/c_linked_list

What Is It?

An implementation of linked lists, written in c. It stores object data in generic pointers.

A variety of utility functions are included for typical list operations.

The list object itself is a c struct, which is defined in the list.h header file. You may browse that file for information about list operation functions.

How Do I Use It?

You may build the linked list source into a static library and include it in your project to give you linked list functionality.

To do so, run make from the command line in the root directory of the list project. After compiling, you will find a liblist.a file in the bin directory of this project. You may have to configure your project's compiler options to include the library correctly.

List struct

The List struct type may be used to declare a the list. Typically a list should be referred to as a pointer to a List, which is itself actually just a single node in the linked list.

#include "list.h"

List list_obj;
List *my_list = &list_obj;
list_sizeof(my_list);

or

#include "list.h"

List *my_list;
list_sizeof(my_list);

Note that most volatile utility functions take a double pointer (an address to a pointer) as a parameter.

Data Types

Note that the data stored within the linked lists's nodes is pointed to by a void pointer. Therefore, you must keep be aware of your own data types, and must cast all pointers to data objects as void pointers (void *).

List Utility Functions

void list_push(List **head, void *data);

Takes a void pointer of data as well as the address of a list pointer and add a node containing that data to the end of the list

Example:

List *list;
char *data = "Some data";
list_push(&list, (void *) data);

void *list_pop(List **head);

Remove the final element of the list and return its data.

Example:

List *list;
char *orig_data = "Original data";
list_push(&list, (void *) orig_data);
char *data;
data = (char *) list_pop(&list);

void list_insert(List **head, void *data);

Insert the data object to the beginning of the list.

Example

List *list;
char *data = "Some data";
list_insert(&list, (void *) data);

unsigned int list_sizeof(List *head);

Get the size of the list.

Example

List *list;
char *data = "Some data";
char *moar_data = "Moar data";
list_push(&list, (void *) data);
list_push(&list, (void *) moar_data);
return list_sizeof(list);
// returns 2

List *list_get(List *head, unsigned int index);

Get the data of the node at the given ordinal number in the list.

Example

List *list;
char *data = "Some data";
list_push(&list, data);
char *retrieved_data = list_get(list, 1);

void list_remove(List **head, unsigned int index);

Delete the item in the list at the given ordinal location (1 is the first).

Example

List *list;
char *data = "Some data";
list_push(&list, data);
list_remove(&list, 1);

Example Program, Tests

You may build a demo project with the included makefile by running make demo from the command line at the root directory of this project. This will build an executable, at bin/list_test.

The example program runs through a handful of scenarios with a list in order to prove its functionality with output to the console.