libft - November 2025

My custom C function library for 42.

Authors

• @0xS4cha

Functions

Character Functions

• ft_isalnum - Checks if a character is alphanumeric
• ft_isalpha - Checks if a character is alphabetic
• ft_isascii - Checks if a character is ASCII
• ft_isdigit - Checks if a character is a digit
• ft_isprint - Checks if a character is printable
• ft_tolower - Converts a character to lowercase
• ft_toupper - Converts a character to uppercase

Memory Functions

• ft_bzero - Sets a memory area to zero
• ft_calloc - Allocates and initializes a memory area
• ft_memchr - Searches for a character in a memory area
• ft_memcmp - Compares two memory areas
• ft_memcpy - Copies a memory area
• ft_memmove - Moves a memory area (handles overlapping)
• ft_memset - Fills a memory area with a character

String Functions

• ft_strchr - Finds the first occurrence of a character
• ft_strdup - Duplicates a string
• ft_striteri - Applies a function to each character with its index
• ft_strjoin - Concatenates two strings
• ft_strlcat - Safely concatenates two strings
• ft_strlcpy - Safely copies a string
• ft_strlen - Calculates the length of a string
• ft_strmapi - Applies a function to each character and creates a new string
• ft_strncmp - Compares two strings up to n characters
• ft_strnstr - Searches for a substring within a string
• ft_strrchr - Finds the last occurrence of a character
• ft_strtrim - Removes specified characters from the start and end
• ft_substr - Extracts a substring
• ft_split - Splits a string into an array using a delimiter

Output Functions

• ft_putchar_fd - Writes a character to a file descriptor
• ft_putendl_fd - Writes a string followed by a newline
• ft_putnbr_fd - Writes a number to a file descriptor
• ft_putstr_fd - Writes a string to a file descriptor

Conversion Functions

• ft_atoi - Converts a string to an integer
• ft_itoa - Converts an integer to a string

Linked List Functions (Bonus)

• ft_lstadd_back - Adds an element at the end of the list
• ft_lstadd_front - Adds an element at the beginning of the list
• ft_lstclear - Deletes and frees all elements of a list
• ft_lstdelone - Deletes and frees a single list element
• ft_lstiter - Iterates through a list and applies a function
• ft_lstlast - Returns the last element of the list
• ft_lstmap - Creates a new list by applying a function
• ft_lstnew - Creates a new list element
• ft_lstsize - Counts the number of elements in a list

Running Tests

To run tests, run the following command

  make fclean bonus

Disclaimer

⚠️ IMPORTANT — Educational use only:

• Do not copy this code for assessed work in 42 or other courses.
• Use this repository for study and reference only.

Feedback

If you have any feedback, please reach out to us at my discord ! <3