diff --git a/Makefile b/Makefile
index f020ce2..5ab790e 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,18 @@ SRC			= ft_isalpha.c \
 			  ft_strnstr.c \
 			  ft_atoi.c \
 			  ft_calloc.c \
-			  ft_strdup.c
+			  ft_strdup.c \
+			  ft_substr.c \
+			  ft_strjoin.c \
+			  ft_strtrim.c \
+			  ft_split.c \
+			  ft_itoa.c \
+			  ft_strmapi.c \
+			  ft_striteri.c \
+			  ft_putchar_fd.c \
+			  ft_putstr_fd.c \
+			  ft_putendl_fd.c \
+			  ft_putnbr_fd.c
 
 OBJ_DIR		= objs
 
diff --git a/ft_itoa.c b/ft_itoa.c
new file mode 100644
index 0000000..0c1416c
--- /dev/null
+++ b/ft_itoa.c
@@ -0,0 +1,75 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_itoa.c                                          :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/07 13:06:35 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/07 13:52:20 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+size_t	malloc_size(int n)
+{
+	size_t	size;
+
+	size = 0;
+	if (n <= 0)
+		size++;
+	while (n)
+	{
+		n /= 10;
+		size++;
+	}
+	return (size);
+}
+
+void	insert_char(char *str, unsigned int nbr, int index)
+{
+	if (!index)
+		return ;
+	str[index] = (nbr % 10) + '0';
+	insert_char(str, nbr / 10, index - 1);
+}
+
+char	*ft_itoa(int n)
+{
+	unsigned int	nbr;
+	char			*str;
+
+	nbr = n;
+	if (n < 0)
+		nbr = n * -1;
+	str = malloc(sizeof(char) * (malloc_size(n) + 1));
+	if (!str)
+		return (NULL);
+	if (nbr == 0)
+		str[0] = '0';
+	else
+	{
+		if (n < 0)
+		{
+			str[0] = '-';
+		}
+		insert_char(str, nbr, malloc_size(n) - 1);
+	}
+	str[malloc_size(n)] = '\0';
+	return (str);
+}
+
+#include "stdio.h"
+
+int	main(int argc, char **argv)
+{
+	char	*str;
+
+	if (argc > 1)
+	{
+		str = ft_itoa(atoi(argv[1]));
+		printf("%s\n", str);
+		free(str);
+	}
+}
diff --git a/ft_putchar_fd.c b/ft_putchar_fd.c
new file mode 100644
index 0000000..bd50ea0
--- /dev/null
+++ b/ft_putchar_fd.c
@@ -0,0 +1,18 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_putchar_fd.c                                    :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/08 17:41:14 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/08 17:42:19 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include <unistd.h>
+
+void	ft_putchar_fd(char c, int fd)
+{
+	write(fd, &c, 1);
+}
diff --git a/ft_putendl_fd.c b/ft_putendl_fd.c
new file mode 100644
index 0000000..bd6dcae
--- /dev/null
+++ b/ft_putendl_fd.c
@@ -0,0 +1,20 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_putendl_fd.c                                    :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/08 17:46:08 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/08 17:47:46 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+#include <unistd.h>
+
+void	ft_putendl_fd(char *s, int fd)
+{
+	ft_putstr_fd(s, fd);
+	write(fd, "\n", 1);
+}
diff --git a/ft_putnbr_fd.c b/ft_putnbr_fd.c
new file mode 100644
index 0000000..d7076cf
--- /dev/null
+++ b/ft_putnbr_fd.c
@@ -0,0 +1,35 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_putnbr_fd.c                                     :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/08 17:50:35 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/08 17:57:02 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+void	write_nbr(unsigned int n, int fd)
+{
+	if (n)
+	{
+		write_nbr(n / 10, fd);
+		ft_putchar_fd(n % 10 + '0', fd);
+	}
+}
+
+void	ft_putnbr_fd(int n, int fd)
+{
+	if (!n)
+		ft_putchar_fd(n % 10 + '0', fd);
+	else if (n < 0)
+	{
+		ft_putchar_fd('-', fd);
+		write_nbr(n * -1, fd);
+	}
+	else
+		write_nbr(n, fd);
+}
diff --git a/ft_putstr_fd.c b/ft_putstr_fd.c
new file mode 100644
index 0000000..083c64f
--- /dev/null
+++ b/ft_putstr_fd.c
@@ -0,0 +1,22 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_putstr_fd.c                                     :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/08 17:43:42 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/08 17:44:38 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+void	ft_putstr_fd(char *s, int fd)
+{
+	while (*s)
+	{
+		ft_putchar_fd(*s, fd);
+		s++;
+	}
+}
diff --git a/ft_split.c b/ft_split.c
new file mode 100644
index 0000000..935efc6
--- /dev/null
+++ b/ft_split.c
@@ -0,0 +1,84 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_split.c                                         :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/06 17:02:58 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/07 13:05:00 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+size_t	strs_size(const char *s, char c)
+{
+	int		i;
+	int		j;
+
+	i = 0;
+	j = 0;
+	while (s[j])
+	{
+		if ((s[j] != c && j == 0) || (s[j] != c && s[j - 1] == c))
+			i++;
+		j++;
+	}
+	return (i);
+}
+
+int	next_match(char	*str, char c)
+{
+	int	i;
+
+	i = 0;
+	while (str[i] != c)
+		i++;
+	return (i);
+}
+
+char	**ft_split(char const *s, char c)
+{
+	char	**strs;
+	int		i;
+	int		j;
+
+	strs = malloc(sizeof(char *) * (strs_size(s, c) + 1));
+	if (!strs)
+		return (free(strs), NULL);
+	i = 0;
+	j = 0;
+	while (s[j])
+	{
+		if ((s[j] != c && j == 0) || (s[j] != c && s[j - 1] == c))
+		{
+			if (s[j] == c)
+				j++;
+			strs[i] = ft_substr(&s[j], 0, next_match((char *) &s[j], c));
+			i++;
+		}
+		j++;
+	}
+	strs[i] = NULL;
+	return (strs);
+}
+/*
+#include <stdio.h>
+
+int	main(void)
+{
+	char	**strs;
+	int		i;
+
+	strs = ft_split("awdawdawd", ' ');
+	i = 0;
+	while (strs[i])
+	{
+		printf("%s\n", strs[i]);
+		free(strs[i]);
+		i++;
+	}
+	free (strs);
+}
+*/
diff --git a/ft_striteri.c b/ft_striteri.c
new file mode 100644
index 0000000..7338aff
--- /dev/null
+++ b/ft_striteri.c
@@ -0,0 +1,23 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_striteri.c                                      :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/08 17:36:38 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/08 17:40:42 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+void	ft_striteri(char *s, void (*f)(unsigned int, char*))
+{
+	unsigned int	i;
+
+	i = 0;
+	while (s[i])
+	{
+		f(i, &s[i]);
+		i++;
+	}
+}
diff --git a/ft_strjoin.c b/ft_strjoin.c
new file mode 100644
index 0000000..46c6665
--- /dev/null
+++ b/ft_strjoin.c
@@ -0,0 +1,38 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_strjoin.c                                       :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/06 13:52:21 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/06 13:56:29 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+char	*ft_strjoin(char const *s1, char const *s2)
+{
+	char	*str;
+	int		i;
+	int		j;
+
+	str = malloc(sizeof(char) * (ft_strlen(s1) + ft_strlen(s2) + 1));
+	if (!str)
+		return (NULL);
+	i = 0;
+	j = 0;
+	while (s1[i])
+	{
+		str[i] = s1[i];
+		i++;
+	}
+	while (s2[j])
+	{
+		str[i + j] = s2[j];
+		j++;
+	}
+	str[i + j] = '\0';
+	return (str);
+}
diff --git a/ft_strmapi.c b/ft_strmapi.c
new file mode 100644
index 0000000..fb1c219
--- /dev/null
+++ b/ft_strmapi.c
@@ -0,0 +1,31 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_strmapi.c                                       :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/08 17:30:25 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/08 17:34:12 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+char	*ft_strmapi(char const *s, char (*f)(unsigned int, char))
+{
+	char			*str;
+	unsigned int	i;
+
+	i = 0;
+	str = malloc(sizeof(char) * (ft_strlen(s) + 1));
+	if (!str)
+		return (NULL);
+	while (s[i])
+	{
+		str[i] = f(i, s[i]);
+		i++;
+	}
+	str[i] = '\0';
+	return (str);
+}
diff --git a/ft_strtrim.c b/ft_strtrim.c
new file mode 100644
index 0000000..545958f
--- /dev/null
+++ b/ft_strtrim.c
@@ -0,0 +1,79 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_strtrim.c                                       :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/06 16:31:38 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/06 17:02:34 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+int	test_charset(char c, char const *set)
+{
+	if (!set[0])
+		return (0);
+	if (c == set[0])
+		return (1);
+	return (test_charset(c, set + 1));
+}
+
+int	end_trim(char const *s1, char const *set)
+{
+	int	i;
+
+	i = 0;
+	if (!s1[0])
+		return (0);
+	while (s1[i])
+		i++;
+	i--;
+	while (test_charset(s1[i], set))
+		i--;
+	return (i);
+}
+
+int	start_trim(char const *s1, char const *set)
+{
+	int	i;
+
+	i = 0;
+	while (test_charset(s1[i], set))
+		i++;
+	return (i);
+}
+
+char	*ft_strtrim(char const *s1, char const *set)
+{
+	int		start;
+	int		end;
+	int		i;
+	char	*str;
+
+	i = 0;
+	start = start_trim(s1, set);
+	end = end_trim(s1, set);
+	str = malloc(sizeof(char) * (end - start + 2));
+	if (!str)
+		return (NULL);
+	while (start + i <= end)
+	{
+		str[i] = s1[i + start];
+		i++;
+	}
+	str[i] = '\0';
+	return (str);
+}
+/*
+int	main(void)
+{
+	char	*test;
+
+	test = ft_strtrim("lorem \n ipsum \t dolor \n sit \t amet", " ");
+	printf("%s\n", test);
+	free(test);
+}
+*/
diff --git a/ft_substr.c b/ft_substr.c
new file mode 100644
index 0000000..e4bf1db
--- /dev/null
+++ b/ft_substr.c
@@ -0,0 +1,37 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_substr.c                                        :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/06 13:20:55 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/06 13:58:18 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+char	*ft_substr(char const *s, unsigned int start, size_t len)
+{
+	size_t	i;
+	char	*sub_str;
+	size_t	s_len;
+
+	s_len = ft_strlen(s);
+	if (start > s_len)
+		len = 0;
+	else if (s_len < (start + len))
+		len = s_len - start;
+	sub_str = malloc(sizeof(char) * (len + 1));
+	if (!sub_str)
+		return (NULL);
+	i = 0;
+	while (i < len)
+	{
+		sub_str[i] = s[start + i];
+		i++;
+	}
+	sub_str[i] = '\0';
+	return (sub_str);
+}
diff --git a/libft.h b/libft.h
index 020d9bf..8085d6a 100644
--- a/libft.h
+++ b/libft.h
@@ -6,7 +6,7 @@
 /*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2025/11/05 09:49:43 by dgaillet          #+#    #+#             */
-/*   Updated: 2025/11/05 21:10:02 by dgaillet         ###   ########lyon.fr   */
+/*   Updated: 2025/11/08 17:56:20 by dgaillet         ###   ########lyon.fr   */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -38,5 +38,16 @@ char	*ft_strnstr(const char *big, const char *little, size_t len);
 int		ft_atoi(const char *nptr);
 void	*ft_calloc(size_t nmemb, size_t size);
 char	*ft_strdup(const char *s);
+char	*ft_substr(char const *s, unsigned int start, size_t len);
+char	*ft_strjoin(char const *s1, char const *s2);
+char	*ft_strtrim(char const *s1, char const *set);
+char	**ft_split(char const *s, char c);
+char	*ft_itoa(int n);
+char	*ft_strmapi(char const *s, char (*f)(unsigned int, char));
+void	ft_striteri(char *s, void (*f)(unsigned int, char*));
+void	ft_putchar_fd(char c, int fd);
+void	ft_putstr_fd(char *s, int fd);
+void	ft_putendl_fd(char *s, int fd);
+void	ft_putnbr_fd(int n, int fd);
 
 #endif