diff --git a/ft_atoi.c b/ft_atoi.c
new file mode 100644
index 0000000..4a2e845
--- /dev/null
+++ b/ft_atoi.c
@@ -0,0 +1,23 @@
+#include "libft.h"
+
+int	ft_atoi(const char *str)
+{
+	int		value;
+	size_t	len;
+	size_t	i;
+	int		n;
+
+	value = 0;
+	len = ft_strlen(str);
+	i = 0;
+	while (i < len)
+	{
+		if (!ft_isdigit(str[i]))
+			return (value);
+		n = (int)(str[i] - '0');
+		value *= 10;
+		value += n;
+		i++;
+	}
+	return (value);
+}
diff --git a/ft_memcmp.c b/ft_memcmp.c
new file mode 100644
index 0000000..3dea5f1
--- /dev/null
+++ b/ft_memcmp.c
@@ -0,0 +1,10 @@
+#include "libft.h"
+
+// int	ft_memcmp(const void *s1, const void *s2, size_t n)
+// {
+// 	const unsigned char *s1_ptr;
+// 	const unsigned char *s2_ptr;
+// 	size_t				i;
+
+// 	while ()
+// }
diff --git a/libft.h b/libft.h
index 31b7d99..8f5c24a 100644
--- a/libft.h
+++ b/libft.h
@@ -2,7 +2,7 @@
 #define LIBFT_A
 
 #include <stddef.h>
-# include <stdlib.h>
+#include <stdlib.h>
 
 /*
 	The ft_isalpha() function tests for
@@ -129,4 +129,12 @@ int	ft_strncmp(const char *s1, const char *s2, size_t n);
 */
 void	*ft_memchr(const void *s, int c, size_t n);
 
+// TODO
+int	ft_memcmp(const void *s1, const void *s2, size_t n);
+
+// TODO
+char	*ft_strnstr(const char *haystack, const char *needle, size_t len);
+
+int	ft_atoi(const char *str);
+
 #endif