diff --git a/src/app/Queue.h b/src/app/Queue.h
index 4fa62bd..5dd5275 100644
--- a/src/app/Queue.h
+++ b/src/app/Queue.h
@@ -23,7 +23,7 @@ public:
         Queue *queueNode = new Queue(value);
         return addNewNodeAtTheEnd(queueNode);
     }
-    unsigned int count()
+    unsigned int count() const
     {
         unsigned int counter(0);
         if(isQueueEmpty(_head->_next))return counter;
@@ -85,7 +85,7 @@ protected:
     {
         _value = value;
     }
-    boolean isQueueEmpty(Queue *node){return node == NULL;}
+    boolean isQueueEmpty(Queue *node) const {return node == NULL;}
     boolean addNewNodeAtTheEnd(Queue *node)
     {
         if(node == NULL) return false;