🧱 Libft

Libft is a foundational C library that reimplements a selection of standard C library functions. It is often the very first project in the 42 curriculum, aiming to ensure students have a solid understanding of memory handling, string manipulation, and linked lists in C.

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📚 Table of Contents

• Overview
• Features
• Installation
• Usage
• File Structure
• Subject Breakdown
• License
• Subject PDF

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📖 Overview

This project consists of re-creating common C standard library functions from <ctype.h>, <string.h>, <stdlib.h>, and <unistd.h>, as well as implementing custom utility functions and linked list manipulation tools.

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✨ Features

Mandatory Functions

• Character checks: ft_isalpha, ft_isdigit, ft_isalnum, ft_isascii, ft_isprint
• Memory manipulation: ft_memset, ft_bzero, ft_memcpy, ft_memmove, ft_memchr, ft_memcmp
• String operations: ft_strlen, ft_strlcpy, ft_strlcat, ft_strchr, ft_strrchr, ft_strncmp, ft_strnstr, ft_strdup
• Type conversions: ft_atoi, ft_tolower, ft_toupper
• Memory allocation: ft_calloc
• Advanced string manipulation: ft_substr, ft_strjoin, ft_strtrim, ft_split, ft_itoa, ft_strmapi, ft_striteri
• File descriptor output: ft_putchar_fd, ft_putstr_fd, ft_putendl_fd, ft_putnbr_fd

Bonus Functions (Linked List Operations)

• ft_lstnew – Create a new list element
• ft_lstadd_front – Add element at the beginning
• ft_lstsize – Count list elements
• ft_lstlast – Get the last element
• ft_lstadd_back – Add element at the end
• ft_lstdelone – Delete a single element
• ft_lstclear – Clear the entire list
• ft_lstiter – Apply a function to each element
• ft_lstmap – Map a function over the list into a new one

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⚙️ Installation

git clone https://github.com/adil-ech/libft
cd libft
make

This will generate libft.a, a static library that you can link with your own C programs using:

gcc your_program.c -L. -lft

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🚀 Usage

In your C file:

#include "libft.h"

Then compile with:

gcc main.c -L. -lft

Ensure that both libft.a and libft.h are present in your project directory or properly linked.

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📁 File Structure

libft/
├── ft_*.c            # Libft function implementations
├── ft_*.h            # Header files (mostly libft.h)
├── Makefile
└── libft.h           # Main header

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📄 Subject Breakdown

✅ Part 1 — Libc Functions

Reimplement standard C functions such as:

• isalpha, isdigit, isalnum, isascii, isprint
• strlen, memset, bzero, memcpy, memmove, strlcpy, strlcat, toupper, tolower
• strchr, strrchr, strncmp, memchr, memcmp
• strnstr, atoi, calloc, strdup

✅ Part 2 — Additional Functions

Implement higher-level string and output utilities:

• substr, strjoin, strtrim, split
• itoa, strmapi, striteri
• putchar_fd, putstr_fd, putendl_fd, putnbr_fd

🔁 Bonus Part — Linked List Functions

If all mandatory functions pass Moulinette:

• ft_lstnew, ft_lstadd_front, ft_lstsize, ft_lstlast
• ft_lstadd_back, ft_lstdelone, ft_lstclear, ft_lstiter, ft_lstmap

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📬 License

This project is part of the 42 Network curriculum and is subject to their academic integrity policy. You are encouraged to use it as a learning resource only.

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📄 Subject PDF

You can read the official 42 Libft subject here:
👉 Libft Subject PDF