Libft

A custom C library implementing core functions from the C Standard Library (libc). This project was developed as part of the WeThinkCode curriculum to deepen understanding of fundamental C programming concepts and library implementation.

Overview

Libft is a collection of commonly-used C library functions, reimplemented from scratch. The project covers memory management, string manipulation, character operations, list operations, and utility functions—all essential building blocks for systems programming.

Getting Started

Prerequisites

• GCC compiler
• Standard Unix/Linux environment
• Make

Installation

Clone the repository and navigate to the directory:

git clone https://github.com/mikefmeyer/libft
cd libft/

Building

Compile the library using Make:

make

This generates libft.a, a static library archive ready for linking.

Usage

Linking with Your Project

To use the library in your C programs:

1. Include the header file in your source code:

   #include "libft.h"

2. Compile your program with the library:

   gcc [your_main.c] [other_files.c] libft.a -o program_name
   ./program_name

Extending the Library

To add new functions to the library:

1. Create your function implementation in a new .c file
2. Declare the function prototype in libft.h
3. Add the object file to the Makefile
4. Run make to recompile

Project Contents

The library includes 80+ implementations covering the following categories:

Character Classification

Character testing functions to identify character types:

• ft_isalpha — Check if character is alphabetic
• ft_isdigit — Check if character is a digit
• ft_isalnum — Check if character is alphanumeric
• ft_isascii — Check if character is ASCII
• ft_isprint — Check if character is printable
• ft_tolower, ft_toupper — Case conversion

String Manipulation

Core string handling and transformation functions:

• ft_strlen — Calculate string length
• ft_strcpy, ft_strncpy — Copy strings
• ft_strcat, ft_strncat — Concatenate strings
• ft_strdup — Duplicate a string
• ft_strcmp, ft_strncmp — Compare strings
• ft_strchr, ft_strrchr — Locate characters in strings
• ft_strstr, ft_strnstr — Find substrings
• ft_strlcat — Safe string concatenation
• ft_strrev — Reverse a string
• ft_strmap, ft_strmapi — Apply functions to strings
• ft_strtrim — Remove whitespace from string
• ft_strsplit — Split string by delimiter
• ft_strjoin — Concatenate strings with allocation
• ft_strsub — Extract substring

String Creation & Deletion

Dynamic string allocation and cleanup:

• ft_strnew — Create new zero-initialized string
• ft_strdel — Free allocated string
• ft_strclr — Clear string contents
• ft_striter, ft_striteri — Iterate over string characters
• ft_strequ, ft_strnequ — Compare string equality

Memory Operations

Low-level memory manipulation:

• ft_memset — Fill memory with value
• ft_memcpy — Copy memory area
• ft_memmove — Move memory area (handles overlap)
• ft_memchr — Search for byte in memory
• ft_memcmp — Compare memory areas
• ft_memccpy — Copy until character found
• ft_bzero — Zero-fill memory
• ft_memalloc — Allocate zero-initialized memory
• ft_memdel — Free allocated memory

Conversion Functions

Convert between data types:

• ft_atoi — Convert string to integer
• ft_itoa — Convert integer to string
• ft_numlen — Get length of number

Output Functions

Direct output to standard output or file descriptors:

• ft_putchar — Write single character
• ft_putstr — Write string
• ft_putnbr — Write number
• ft_putendl — Write string with newline
• ft_putchar_fd — Write character to file descriptor
• ft_putstr_fd — Write string to file descriptor
• ft_putnbr_fd — Write number to file descriptor
• ft_putendl_fd — Write string with newline to file descriptor

List Operations

Linked list structure and manipulation:

• ft_lstnew — Create new list node
• ft_lstadd — Add node to list
• ft_lstdel — Delete entire list
• ft_lstdelone — Delete single node
• ft_lstiter — Iterate over list nodes

Utility Functions

Miscellaneous helper functions:

• ft_swap — Swap two integers
• ft_pwr — Calculate power
• ft_sqrt — Calculate square root
• ft_foreach — Apply function to array elements
• ft_wordcount — Count words in string
• ft_wordlen — Get word length in string
• ft_wordcount — Count words separated by delimiter

I/O Functions

Advanced input operations:

• get_next_line — Read file line by line (bonus function)

Helper Functions

Utility functions for memory management:

• free_her — Free null-terminated string array
• join_her — Join string array with delimiter

License

Created as part of WeThinkCode learning curriculum.