tasks a-s

Task/Queue-Definition/Scheme/queue-definition-1.ss

@@ -0,0 +1,15 @@
+(define (make-queue)
+  (make-vector 1 '()))
+
+(define (push a queue)
+  (vector-set! queue 0 (append (vector-ref queue 0) (list a))))
+
+(define (empty? queue)
+  (null? (vector-ref queue 0)))
+
+(define (pop queue)
+  (if (empty? queue)
+      (error "can not pop an empty queue")
+      (let ((ret (car (vector-ref queue 0))))
+        (vector-set! queue 0 (cdr (vector-ref queue 0)))
+        ret)))