--- a/baum.c	Sun Mar 02 16:43:07 2008 +0100
+++ b/baum.c	Sun Mar 16 10:40:53 2008 +0100
@@ -44,6 +44,10 @@
 struct Node* newNode(char* name, unsigned char value) {
 	struct Node* node;
 	node = (struct Node*) malloc(sizeof(struct Node));
+	if (node == NULL) {
+		perror("unable to allocate memory");
+		exit(10);
+	}
 	strcpy(node->name, name);
 	node->value = value;
 	node->right = 0;
@@ -91,12 +95,13 @@
 
 /* print */
 void printNode(struct Node* node, int level) {
-	if (node != NULL) {
-		while (level-- > 0) {
-			fprintf(stderr, "\t");
-		}
-		fprintf(stderr, "%s (%d|%c)\n", node->name, node->value, node->value);
+	if (node == NULL) {
+		return;
 	}
+	while (level-- > 0) {
+		fprintf(stderr, "\t");
+	}
+	fprintf(stderr, "%s (%d|%c)\n", node->name, node->value, node->value);
 }
 
 void printTree(struct Node* root, int level) {
@@ -117,6 +122,10 @@
 	struct Stackitem* tmp;
 	struct Stackitem* new;
 	new = (struct Stackitem*) malloc(sizeof(struct Stackitem));
+	if (new == NULL) {
+		perror("unable to allocate memory");
+		exit(10);
+	}
 	new->node = node;
 	tmp = stack;
 	stack = new;
@@ -154,9 +163,13 @@
 	last_indent = -1;
 	last_node = NULL;
 	file = fopen(filename, "r");
+	if (file == NULL) {
+		perror("unable to open file");
+		exit(10);
+	}
 
 	while ((c = getc(file)) != EOF) {
-		if (c == '#') { /* comment */
+		if (c == '#') {  /* comment */
 			while ((c = getc(file)) != '\n') {
 			}
 		}