📚 Libft - 42 School Project

A complete implementation of the fundamental C library required for the 42 curriculum. This library includes recreated standard C functions, additional utility functions, and bonus linked list operations.

🎯 Project Overview

Libft is the first project at 42 School where students recreate essential C standard library functions and create additional utilities. This project serves as the foundation for many future 42 projects.

Key Requirements:

• ✅ All functions follow Norminette (42's coding standard)
• ✅ No forbidden functions (only malloc, free, and write where allowed)
• ✅ Strict memory management (no memory leaks)
• ✅ Compiled with -Wall -Wextra -Werror flags

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📋 Function Reference

Part 1: Libc Functions (23 functions)

Standard C library functions reimplemented without using their original versions.

Function	Description
Character Checks
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_toupper	Convert character to uppercase
ft_tolower	Convert character to lowercase
String Functions
ft_strlen	Calculate string length
ft_strchr	Locate character in string
ft_strrchr	Locate character in string from end
ft_strncmp	Compare strings up to n bytes
ft_strnstr	Locate substring in string
ft_strlcpy	Size-bounded string copy
ft_strlcat	Size-bounded string concatenation
ft_strdup	Duplicate string (malloc)
Memory Functions
ft_memset	Fill memory with constant byte
ft_bzero	Zero a byte string
ft_memcpy	Copy memory area
ft_memmove	Copy memory area (handles overlap)
ft_memchr	Scan memory for character
ft_memcmp	Compare memory areas
Conversion & Allocation
ft_atoi	Convert string to integer
ft_calloc	Allocate and zero memory

Part 2: Additional Functions (11 functions)

Custom utility functions that extend standard library functionality.

Function	Description
String Manipulation
ft_substr	Extract substring from string
ft_strjoin	Concatenate two strings (malloc)
ft_strtrim	Trim characters from string ends
ft_split	Split string by delimiter into array
ft_itoa	Convert integer to string
Function Application
ft_strmapi	Apply function to each character with index
ft_striteri	Iterate string and apply function
Output Functions
ft_putchar_fd	Output character to file descriptor
ft_putstr_fd	Output string to file descriptor
ft_putendl_fd	Output string + newline to fd
ft_putnbr_fd	Output integer to file descriptor

Bonus: Linked List Functions (9 functions)

Complete linked list manipulation toolkit using t_list structure.

Function	Description
ft_lstnew	Create new list element
ft_lstadd_front	Add element at beginning of list
ft_lstadd_back	Add element at end of list
ft_lstsize	Count elements in list
ft_lstlast	Get last element of list
ft_lstdelone	Delete single list element
ft_lstclear	Delete and free entire list
ft_lstiter	Iterate list and apply function
ft_lstmap	Iterate, apply function, create new list

t_list structure:

typedef struct s_list
{
    void            *content;
    struct s_list   *next;
}   t_list;

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🔧 Compilation & Usage

Building the Library

# Clone the repository
git clone https://github.com/enekomb/libft.git
cd libft

# Compile mandatory functions only
make

# Compile with bonus functions
make bonus

# Clean object files
make clean

# Clean everything (objects + library)
make fclean

# Recompile from scratch
make re

This creates libft.a, a static library containing all the functions.

Using in Your Projects

1. Include the header in your C files:

#include "libft.h"

2. Compile your project with the library:

# Basic compilation
cc your_file.c -L. -lft -o your_program

# With flags
cc -Wall -Wextra -Werror your_file.c -L. -lft -o your_program

Example Usage:

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

int main(void)
{
    char *str = ft_strdup("Hello, 42!");
    char **words = ft_split("one two three", ' ');
    t_list *list = ft_lstnew("Node 1");
    
    ft_putendl_fd(str, 1);
    
    // Remember to free allocated memory
    free(str);
    // ... free words array and list
    
    return (0);
}

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🧪 Testing

While this repository focuses on implementation, you can test the functions using:

• Tripouille/libftTester
• jtoty/Libftest
• alelievr/libft-unit-test

# Example with Tripouille's tester
git clone https://github.com/Tripouille/libftTester.git
cd libftTester
make

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📁 Project Structure

LIBFT/
├── libft.h          # Header file with all prototypes and t_list struct
├── Makefile         # Compilation rules
├── ft_*.c           # 43 function implementation files
└── README.md        # This file

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⚙️ Technical Details

• Compiler: cc (clang/gcc)
• Flags: -Wall -Wextra -Werror
• Standard: C89/C90 compatible
• Archive tool: ar rcs
• Norminette: v3.x compliant

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📖 Learning Outcomes

This project teaches:

• 🔹 Deep understanding of C standard library internals
• 🔹 Manual memory management and leak prevention
• 🔹 Pointer manipulation and edge case handling
• 🔹 Makefile creation and library archiving
• 🔹 Data structures (linked lists)
• 🔹 Strict coding standards (Norminette)

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⚠️ Academic Integrity

This repository is shared for educational and portfolio purposes only.

For 42 Students:

• 🚫 Do not copy this code for your own Libft project
• ✅ Use it as a reference to understand concepts
• ✅ Learn from the implementation approaches
• ✅ Write your own original code

42's core values are learning through practice, peer collaboration, and genuine problem-solving.

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👤 Author

Eneko Muñoz Bordona

• GitHub: @enekomb
• LinkedIn: eneko-muñoz-bordona
• Email: enekomunoz@gmail.com

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📄 License

All rights reserved. This code is provided for educational purposes only.

If you're a 42 student, please respect the school's policies on code sharing and academic integrity.

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Made with ❤️ at 42 Urduliz