libft

Libft project for 42 School.

This project is about coding a C library.

It will contain a lot of general purpose functions your programs will rely upon.

Introduction

C programming can be very tedious when one doesn’t have access to the highly useful standard functions. This project is about understanding the way these functions work, implementing and learning to use them. Your will create your own library. It will be helpful since you will use it in your next C school assignments.

Take the time to expand your libft throughout the year. However, when working on a new project, don’t forget to ensure the functions used in your library are allowed in the project guidelines.

Part 1: Libc functions

To begin, you must redo a set of functions from the libc. Your functions will have the same prototypes and implement the same behaviors as the originals. They must comply with the way they are defined in their man. The only difference will be their names. They will begin with the “ft_” prefix. For instance, strlen becomes ft_strlen.

Some of the functions’ prototypes you have to redo use the restrict qualifier. This keyword is part of the c99 standard. It is therefore forbidden to include it in your own prototypes and to compile your code with the -std=c99 flag.

You must write your own function implementing the following original ones. They do not require any external functions:

isalpha
isdigit
isalnum
isascii
isprint
strlen
memset
bzero
memcpy
memmove
strlcpy
strlcat
toupper
tolower
strchr
strrchr
strncmp
memchr
memcmp
strnstr
atoi

In order to implement the two following functions, you will use malloc():

calloc
strdup

Part 2: Additional functions

In this second part, you must develop a set of functions that are either not in the libc, or that are part of it but in a different form.

Some of the following functions can be useful for writing the functions of Part 1.

ft_substr

Prototype: char *ft_substr(char const *s, unsigned int start, size_t len);
Turn in files: None
Parameters:
- s: The string from which to create the substring.
- start: The start index of the substring in the string s.
- len: The maximum length of the substring.
Return value: The substring. NULL if the allocation fails.
External functs.: malloc
Description: Allocates (with malloc(3)) and returns a substring from the string s. The substring begins at index start and is of maximum size len.

ft_strjoin

Prototype: char *ft_strjoin(char const *s1, char const *s2);
Turn in files: None
Parameters:
- s1: The prefix string.
- s2: The suffix string.
Return value: The new string. NULL if the allocation fails.
External functs.: malloc
Description: Allocates (with malloc(3)) and returns a new string, which is the result of the concatenation of s1 and s2.

ft_strtrim

Prototype: char *ft_strtrim(char const *s1, char const *set);
Turn in files: None
Parameters:
- s1: The string to be trimmed.
- set: The reference set of characters to trim.
Return value: The trimmed string. NULL if the allocation fails.
External functs.: malloc
Description: Allocates (with malloc(3)) and returns a copy of s1 with the characters specified in set removed from the beginning and the end of the string.

ft_split

Prototype: char **ft_split(char const *s, char c);
Turn in files: None
Parameters:
- s: The string to be split.
- c: The delimiter character.
Return value: The array of new strings resulting from the split. NULL if the allocation fails.
External functs.: malloc, free Allocates (with malloc(3)) and returns an array of strings obtained by splitting s using the character c as a delimiter. The array must end with a NULL pointer.

ft_itoa

Prototype: char *ft_itoa(int n);
Turn in files: None
Parameters:
- n: the integer to convert.
Return value: The string representing the integer. NULL if the allocation fails.
External functs.: malloc
Description: Allocates (with malloc(3)) and returns a string representing the integer received as an argument. Negative numbers must be handled.

ft_strmapi

Prototype: char *ft_strmapi(char const *s, char (*f)(unsigned int, char));
Turn in files: None
Parameters:
- s: The string on which to iterate.
- f: The function to apply to each character.
Return value: The string created from the successive applications of f. Returns NULL if the allocation fails.
External functs.: malloc
Description: Applies the function f to each character of the string s, and passing its index as first argument to create a new string (with malloc(3)) resulting from successive applications of f.

ft_striteri

Prototype: void ft_striteri(char *s, void (*f)(unsigned int, char*));
Turn in files: None
Parameters:
- s: The string on which to iterate.
- f: The function to apply to each character.
Return value: None
External functs.: None
Description: Applies the function f on each character of the string passed as argument, passing its index as first argument. Each character is passed by address to f to be modified if necessary.

ft_putchar_fd

Prototype: void ft_putchar_fd(char c, int fd);
Turn in files: None
Parameters:
- c: The character to output.
- fd: The file descriptor on which to write.
Return value: None
External functs.: write
Description: Outputs the character c to the given file descriptor.

ft_putstr_fd

Prototype: void ft_putstr_fd(char *s, int fd);
Turn in files: None
Parameters:
- s: The string to output.
- fd: The file descriptor on which to write.
Return value: None
External functs.: write
Description: Outputs the string s to the given file descriptor.

ft_putendl_fd

Prototype: void ft_putendl_fd(char *s, int fd);
Turn in files: None
Parameters:
- s: The string to output.
- fd: The file descriptor on which to write.
Return value: None
External functs.: write
Description: Outputs the string s to the given file descriptor followed by a newline.

ft_putnbr_fd

Prototype: void ft_putnbr_fd(int n, int fd);
Turn in files: None
Parameters:
- n: The integer to output.
- fd: The file descriptor on which to write.
Return value: None
External functs.: write
Description: Outputs the integer n to the given file descriptor.

jmorillo42/libft