1 files changed, 1 insertions, 1 deletions
diff --git a/trie.cpp b/trie.cpp
index 729277bd..a3446a97 100644
--- a/trie.cpp
+++ b/trie.cpp
@@ -68,7 +68,7 @@ int trie<T>::push_back (const char* key, const T& item) {
 }
 
 template <class T>
-T& trie<T>::operator[] (char* key) {
+T& trie<T>::operator[] (const char* key) {
 	trie_node<T>* n = this->root->child;
 	char* subkey = key;