make ListIterator continue working on a changing list

1 files changed, 6 insertions, 4 deletions

diff --git a/backend/List.h b/backend/List.h
index 1af0b35..3bdbb23 100644
--- a/backend/List.h
+++ b/backend/List.h
@@ -10,6 +10,7 @@ class ListIterator;
 
 template <typename T>
 struct ListLink {
+	friend class ListIterator<T>;
 	ListLink<T> * prev;
 	ListLink<T> * next;
 	T value;
@@ -24,7 +25,7 @@ public:
 public:
 	size_t size() const;
 
-	void push_back(T & el);
+	void push_back(const T & el);
 	void remove(const T & val);
 
 	void pop_back();
@@ -33,11 +34,12 @@ public:
 
 	T & operator [] (size_t index) const;
 
-	ListIterator<T> begin() const;
-	ListIterator<T> end() const;
-	ListRange<T> range() const;
+	ListIterator<T> begin();
+	ListIterator<T> end();
+	ListRange<T> range();
 
 private:
+	friend class ListRange<T>;
 	ListLink<T> * head = nullptr;
 	ListLink<T> * tail = nullptr;
 	size_t length = 0;