Queue

queue.c

@@ -0,0 +1,81 @@
+#include <stdlib.h>
+#include <ctype.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+typedef struct node {
+    void *content;
+    struct node *next;
+}Node;
+
+typedef struct queue {
+    Node *first;
+    Node *last;
+    size_t w;
+}Queue;
+
+Queue *new_queue(size_t w) {
+    Queue *q = malloc(sizeof(Queue));
+    q->first = NULL;
+    q->last = NULL;
+    q->w = w;
+    return q;
+}
+
+bool is_empty(Queue *q) {
+    return !q->first;
+}
+
+void enqueue(void *content, Queue *q) {
+    Node *n = malloc(sizeof(Node));
+    n->content = content;
+    n->next = NULL;
+    if (is_empty(q))
+        q->first = n;
+    else
+        q->last->next = n;
+    q->last = n;
+}
+
+void *dequeue(Queue *q) {
+    if (is_empty(q))
+        return NULL;
+    void *r = q->first->content;
+    Node *n = q->first;
+    q->first = q->first->next;
+    free(n);
+    if (is_empty(q))
+        q->last = NULL;
+    return r;
+}
+
+void destroy(Queue *q) {
+    while (!is_empty(q)) {
+        free(dequeue(q));
+    }
+    free(q);
+}
+
+int main() {
+    Queue *q = new_queue(sizeof(int));
+    int *a = malloc(sizeof(int));
+    int *b = malloc(sizeof(int));
+    int *c = malloc(sizeof(int));
+    int *d = malloc(sizeof(int));
+    *a=1;
+    *b=2;
+    *c=3;
+    *d=-1;
+    enqueue(a, q);
+    printf("%d\n", *((int*)dequeue(q)));
+    enqueue(b, q);
+    enqueue(c, q);
+    enqueue(d, q);
+    while(!is_empty(q)) {
+        printf("%d\n", *((int*)dequeue(q)));
+    }
+    destroy(q);
+    return 0;
+
+}
+