diff --git a/ex00/ft_strdup.c b/ex00/ft_strdup.c
index 7bb0fdf..7095da2 100644
--- a/ex00/ft_strdup.c
+++ b/ex00/ft_strdup.c
@@ -37,7 +37,7 @@ char	*ft_strdup(char *src)
 {
 	char	*new_str;
 
-	new_str = malloc(8 * ft_strlen(src));
+	new_str = malloc(sizeof(char *) * ft_strlen(src));
 	ft_strcpy(new_str, src);
 	return (new_str);
 }
diff --git a/ex01/ft_range.c b/ex01/ft_range.c
index d13f43d..7541273 100644
--- a/ex01/ft_range.c
+++ b/ex01/ft_range.c
@@ -18,7 +18,7 @@ int	*ft_range(int min, int max)
 	int	idx;
 
 	if (min >= max)
-		return ((void *) 0);
+		return (NULL);
 	range = malloc(sizeof(int) * (max - min));
 	idx = -1;
 	while (++idx < max - min)
diff --git a/ex02/ft_ultimate_range.c b/ex02/ft_ultimate_range.c
index 3f022d1..2ebb672 100644
--- a/ex02/ft_ultimate_range.c
+++ b/ex02/ft_ultimate_range.c
@@ -19,7 +19,7 @@ int	ft_ultimate_range(int **range, int min, int max)
 
 	if (min >= max)
 	{
-		*range = (void *) 0;
+		*range = NULL;
 		return (-1);
 	}
 	*range = malloc(sizeof(int) * (max - min));
diff --git a/ex03/ft_strjoin.c b/ex03/ft_strjoin.c
index a61fd98..fae170b 100644
--- a/ex03/ft_strjoin.c
+++ b/ex03/ft_strjoin.c
@@ -77,7 +77,7 @@ int	main(void)
 	size = 5;
 	// sep = "<DELIM>";
 	sep = "";
-	strs = malloc(sizeof((char *) 0) * size);
+	strs = malloc(sizeof(char*) * size);
 	strs[0] = "First";
 	strs[1] = "Second";
 	strs[2] = "Third";
diff --git a/ex04/ft_convert_base.c b/ex04/ft_convert_base.c
index dd30864..fae2127 100644
--- a/ex04/ft_convert_base.c
+++ b/ex04/ft_convert_base.c
@@ -60,7 +60,7 @@ char	*ft_to_base(int nbr, char *base_to)
 
 	base_len = is_valid_base(base_to, 1);
 	if (!base_len)
-		return ((void *) 0);
+		return (NULL);
 	result = malloc(sizeof(char) * MAX_OUTPUT_LEN);
 	idx = -1;
 	while (++idx < MAX_OUTPUT_LEN)