feat: add ft_memset function

ft_memset.c

@@ -0,0 +1,16 @@
+#include "libft.h"
+
+void	*ft_memset(void *b, int c, size_t len)
+{
+	char	*tmp;
+	size_t	i;
+
+	tmp = (char *)b;
+	i = 0;
+	while (i < len)
+	{
+		tmp[i] = (char)c;
+		i++;
+	}
+	return (b);
+}

libft.h

@@ -1,6 +1,7 @@
 #ifndef LIBFT_A
 #define LIBFT_A
 
+#include <stddef.h>
 # include <stdlib.h>
 
 /*
@@ -47,4 +48,11 @@ int	ft_isprint(int c);
 */
 size_t	ft_strlen(const char *s);
 
+/*
+	The ft_memset() function writes len 
+	bytes of value c (converted to an 
+	unsigned char) to the string b.
+*/
+void	*ft_memset(void *b, int c, size_t len); 
+
 #endif