erster Commit

1 files changed, 86 insertions, 0 deletions

diff --git a/queue.c b/queue.c
new file mode 100644
index 0000000..fdacca5
--- /dev/null
+++ b/queue.c
@@ -0,0 +1,86 @@
+/* Standard C */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+/* Project */
+#include "util.h"
+
+typedef int T;
+
+struct queue_item {
+        struct queue_item *next;
+        T data;
+};
+
+struct queue {
+        struct queue_item *head, *tail;
+};
+
+void
+queue_init(struct queue *queue)
+{
+        queue->head = NULL;
+}
+
+void
+queue_put(struct queue *queue, T data)
+{
+        struct queue_item *new_item;
+
+        if ( (new_item = malloc(sizeof(*new_item))) != NULL ) {
+                struct queue_item *tmp = queue->tail;
+                new_item->data = data;
+                queue->tail = new_item;
+                if ( queue->head == NULL )
+                        queue->head = queue->tail;
+                else
+                        tmp->next = queue->tail;
+        }
+        else
+                ERROR("out of memory");
+}
+
+bool
+queue_get(struct queue *queue, T *data)
+{
+        if ( queue->head != NULL ) {
+                struct queue_item *next = queue->head->next;
+                *data = queue->head->data;
+                free(queue->head);
+                queue->head = next;
+
+                return true;
+        }
+        else
+                return false;
+}
+
+bool
+queue_empty(struct queue *queue)
+{
+        return queue->head == NULL;
+}
+
+int
+main()
+{
+        struct queue queue[1];
+
+        queue_init(queue);
+
+        for ( int i = 0; i != 10; ++i )
+                queue_put(queue, i);
+
+        while ( !queue_empty(queue) ) {
+                int i;
+                if ( queue_get(queue, &i) )
+                        printf("%d\n", i);
+                else
+                        ERROR("this shouldn't happen!");
+        }
+        return EXIT_SUCCESS;
+}
+
+
+