Libft

Description

Libft is the first project at 42 School where you create your own C library. It involves re-implementing standard libc functions and additional utility functions that will be useful for future projects. This library serves as a fundamental tool to understand how C functions work internally and to use them in upcoming 42 cursus projects.

Contents

• Requirements
• Project Structure
• Compilation
• Implemented Functions
• Usage

Requirements

• gcc compiler.
• Unix-based operating system (Linux or macOS).
• Make (for executing the Makefile).

Project Structure

📦 libft/
├── libft.h
├── Makefile
└── ft_*.c

• libft.h: Header file containing all function declarations.
• Makefile: File to compile the library and manage compilation rules.
• ft_*: Source files of mandatory functions.

Compilation

To compile the library, run:

make

This will generate the libft.a file.

Additional commands:

• make clean: Removes object files.
• make fclean: Removes object files and the libft.a library.
• make re: Cleans and recompiles everything.

Implemented Functions

Part 1 - Libc Functions

The following standard libc functions have been re-implemented with the ft_ prefix:

• 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

Additional utility functions not included in the standard libc:

• ft_substr: Extracts a substring from a given string.
• ft_strjoin: Concatenates two strings into a new string.
• ft_strtrim: Trims characters from the start and end of a string based on a given set.
• ft_split: Splits a string into an array of strings using a specified delimiter.
• ft_itoa: Converts an integer to a string.
• ft_strmapi and ft_striteri: Applies a function to each character of a string.
• Output functions: ft_putchar_fd, ft_putstr_fd, ft_putendl_fd, ft_putnbr_fd.

Usage

You can include this library in your C projects:

#include "libft.h"

int main(void) {
    char *str = ft_strdup("Hello World");
    ft_putstr_fd(str, 1);
    free(str);
    return 0;
}

Compile your project using libft.a:

gcc main.c -L. -lft -o my_program