successors is const

[slidingtile] / sliding_tile_lib.cc

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index e4f2f12723591ac320a56813eb8b3b306eaace30..5284dab95e4d4f707310f4fab44f996fdd8f56f8 100644 (file)
--- a/sliding_tile_lib.cc
+++ b/sliding_tile_lib.cc
@@ -133,7 +133,7 @@ int Board::distance(const InvertedBoard& invo) const {
   return dist;
 }
 
-std::vector<Step*> Step::successors(std::shared_ptr<Step> shared_this) {
+std::vector<Step*> Step::successors(std::shared_ptr<Step> shared_this) const {
   std::vector<Step*> suc;
   signed char hole_pos = board.hole();
   for (int i = 0; adjacent[hole_pos][i] > 0; i++) {