added queue in linkedlist implementation in Java

Author: jenlky

Data Structures/Queue/queue_linkedlist_implementation.java

@@ -0,0 +1,41 @@
+public class LinkedQueueOfStrings {
+  private Node first, last;
+
+  private class Node {
+    String item;
+    Node next;
+  }
+
+  public boolean isEmpty() {
+    return first != null;
+  }
+
+  public void enqueue(String item) {
+    Node oldlast = last;
+    last = new Node();
+    last.item = item;
+    last.next = null;
+    if (isEmpty()) {
+      first = last;
+    } else {
+      oldlast.next = last;
+    }
+  }
+
+  public String dequeue() {
+    String item = first.item;
+    first = first.next;
+    if (isEmpty()) {
+      last = null;
+    } 
+    return item;
+  }
+
+  public static void main(String[] args) {
+    LinkedQueueOfStrings<String> queue = new LinkedQueueOfStrings<String>();
+    queue.enqueue("a");
+    queue.enqueue("b");
+    queue.enqueue("c");
+    
+  }
+}