📚 Libft - My First C Library

"The beginning of wisdom is the definition of terms." - Socrates

Libft is my implementation of essential C standard library functions, created as the foundational project at 1337 School. This project taught me the fundamentals of C programming by rebuilding core functions from scratch.

🎯 Project Overview

The goal was to create my own C library containing a collection of functions that are essential for C programming. This library serves as the foundation for all future projects at 1337 School.

What I Built

• 42 functions recreating essential libc functions
• Memory management functions
• String manipulation utilities
• Character validation functions
• Linked list manipulation functions (bonus part)

🛠️ Functions Implemented

Part 1 - Libc Functions

Functions that exist in the C standard library:

Function	Description
ft_strlen	Calculate string length
ft_strcpy	Copy strings
ft_strcmp	Compare strings
ft_memset	Fill memory with bytes
ft_memcpy	Copy memory area
ft_isalpha	Check if alphabetic
ft_isdigit	Check if digit
ft_toupper	Convert to uppercase
ft_tolower	Convert to lowercase
And many more...

Part 2 - Additional Functions

Functions not in libc or with different prototypes:

Function	Description
ft_substr	Extract substring
ft_strjoin	Concatenate strings
ft_strtrim	Trim characters from string
ft_split	Split string by delimiter
ft_itoa	Convert integer to string
ft_putchar_fd	Output char to file descriptor
ft_putstr_fd	Output string to file descriptor

Bonus Part - Linked Lists

Function	Description
ft_lstnew	Create new list element
ft_lstadd_front	Add element at beginning
ft_lstsize	Count list elements
ft_lstlast	Get last element
ft_lstadd_back	Add element at end
ft_lstclear	Delete and free list

🚀 How to Use

Compilation

# Compile the library
make

# Compile with bonus functions
make bonus

# Clean object files
make clean

# Clean everything
make fclean

# Recompile everything
make re

Usage Example

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

int main(void)
{
    char *str = "Hello, 1337!";
    char *substr;
    
    printf("Original: %s\n", str);
    printf("Length: %zu\n", ft_strlen(str));
    
    substr = ft_substr(str, 7, 4);
    printf("Substring: %s\n", substr);
    
    free(substr);
    return (0);
}

Compilation with Your Project

gcc -Wall -Wextra -Werror your_program.c -L. -lft -o your_program

📋 Requirements & Norms

• Language: C
• Norm: 1337/42 School coding standard
• Functions: No global variables
• Memory: All heap-allocated memory must be freed
• Error handling: Functions should not crash unexpectedly

Compilation Flags

-Wall -Wextra -Werror

🎓 What I Learned

This project was crucial for understanding:

• Memory Management: Manual allocation and deallocation
• Pointer Manipulation: Working with different levels of indirection
• String Operations: Understanding how strings work at a low level
• Linked Lists: Dynamic data structures and memory allocation
• Makefile: Automating compilation process
• Code Organization: Structuring a library project
• Testing: Writing comprehensive tests for each function

🧪 Testing

I created comprehensive tests to verify each function works correctly:

# Example test structure
make test
./test_libft

📁 Project Structure

libft/
├── src/           # Source files (.c)
├── include/       # Header files (.h)  
├── Makefile       # Compilation rules
└── README.md      # This file

💭 Reflections

Building Libft from scratch gave me a deep appreciation for the standard library functions we often take for granted. Every strlen() call, every malloc(), every string operation - I now understand what happens under the hood.

This project laid the foundation for all my subsequent C projects at 1337 School and taught me the importance of:

• Writing clean, readable code
• Proper memory management
• Comprehensive testing
• Following coding standards

---

This project was completed as part of the 1337 School curriculum (42 Network).

Author: Hiba
School: 1337 (42 Network)
Year: 2024