Libft

Custom C library implemented as part of the 42 cursus.
The goal of this project is to recreate a subset of the standard C library functions, plus a few extra utilities, and bundle them into a reusable static library: libft.a.

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📚 Project Overview

School: 42 Beirut Project: Libft
Language: C

In libft, you re-implement low-level functions for:

• character and string handling
• memory management
• conversions
• basic linked list utilities (bonus)

This library will be reused in many later 42 projects, so the focus is on:

• writing clean, reliable C code
• respecting the 42 Norm
• understanding pointers, memory, and edge cases

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🧩 Contents

Update this list according to what you actually implemented.

1️⃣ Mandatory – libc-like functions

Functions for:

• Character checks & transforms
  • ft_isalpha, ft_isdigit, ft_isalnum, ft_isascii, ft_isprint
  • ft_toupper, ft_tolower
• Strings
  • ft_strlen, ft_strlcpy, ft_strlcat
  • ft_strchr, ft_strrchr, ft_strncmp, ft_strnstr
  • ft_strdup
• Memory
  • ft_memset, ft_bzero
  • ft_memcpy, ft_memmove
  • ft_memchr, ft_memcmp
• Allocation & conversion
  • ft_calloc
  • ft_atoi

2️⃣ Additional functions

More useful helpers, for example:

• String creation & transformation:
  ft_substr, ft_strjoin, ft_strtrim, ft_split, ft_strmapi, ft_striteri
• Number & file descriptor utilities:
  ft_itoa, ft_putchar_fd, ft_putstr_fd, ft_putendl_fd, ft_putnbr_fd

3️⃣ Bonus – linked list utilities (if enabled)

If you compiled with make bonus, the library also includes:

• t_list structure
• List manipulation:
  • ft_lstnew, ft_lstadd_front, ft_lstadd_back
  • ft_lstsize, ft_lstlast
  • ft_lstdelone, ft_lstclear
  • ft_lstiter, ft_lstmap

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🗂 Project Structure

.
├── Makefile
├── libft.h
├── *.c          # implementation files
├── bonus/*.c    # (optional) bonus list functions
└── README.md

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⚙️ Building the Library

Clone the repository and build:

git clone https://github.com/M677871/Libft.git
cd Libft

# Build mandatory part
make

# Build bonus part (if implemented)
make bonus

# Clean object files
make clean

# Remove objects + libft.a
make fclean

# Rebuild from scratch
make re

After make, you should have:

libft.a   # static library

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🧪 Using Libft in Your Project

1. Copy libft.a and libft.h into your project, or add this repo as a submodule.

2. Include the header in your C files:

   #include "libft.h"

3. Compile and link with libft.a:

   gcc -Wall -Wextra -Werror main.c libft.a -o my_program

Minimal example

#include "libft.h"
#include <stdio.h>

int main(void)
{
    const char *s = "Hello, libft!";
    size_t len = ft_strlen(s);

    printf("Length: %zu\n", len);
    return 0;
}

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✅ Testing

You can test the library with your own mains or with external testers such as
Tripouille/libftTester:

# inside the tester directory, with LIBFT_PATH set correctly
make m      # mandatory tests
make b      # bonus tests
make a      # all tests

Don’t forget to also:

• run Norminette on .c and .h files
• check behavior on edge cases (NULL, empty strings, overflows, etc.)

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🧠 Notes & Learning Goals

Working on libft helps to:

• understand how standard C functions work internally
• practice pointer arithmetic and memory management
• learn to debug segmentation faults and undefined behavior
• get comfortable with 42’s Norm and project workflow

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📎 License

This project is part of the 42 curriculum.
You can reuse this code in your own 42 projects as allowed by the school’s rules.

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👤 Author

• Login: M677871
• GitHub: @M677871