fix: Prüfe, ob 'data' wirklich dereferenziert werden kann

1 files changed, 7 insertions, 7 deletions

diff --git a/stack.c b/stack.c
index fa89974..775269d 100644
--- a/stack.c
+++ b/stack.c
@@ -1,7 +1,7 @@
 /* Standard C */
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <stdbool.h>
 
 /* Project */
 #include "util.h"
@@ -10,7 +10,7 @@ typedef int T;
 
 struct stack_item {
         struct stack_item *next;
-        T data;
+        T                  data;
 };
 
 struct stack {
@@ -31,7 +31,7 @@ stack_push(struct stack *stack, T data)
         if ( (new_item = malloc(sizeof(*new_item))) != NULL ) {
                 new_item->data = data;
                 new_item->next = stack->head;
-                stack->head = new_item;
+                stack->head    = new_item;
         }
         else
                 ERROR("out of memory");
@@ -42,7 +42,10 @@ stack_pop(struct stack *stack, T *data)
 {
         if ( stack->head != NULL ) {
                 struct stack_item *next = stack->head->next;
-                *data = stack->head->data;
+
+                if ( data != NULL ) {
+                        *data = stack->head->data;
+                }
                 free(stack->head);
                 stack->head = next;
 
@@ -93,6 +96,3 @@ main()
 
         return EXIT_SUCCESS;
 }
-
-
-