From f92e9dcac70dc0859e1cf176b84b39c42f677e3e Mon Sep 17 00:00:00 2001
From: Scott Worley <scottworley@scottworley.com>
Date: Sat, 9 Jan 2016 02:42:11 -0800
Subject: [PATCH] successors is const

---
 sliding_tile_lib.cc | 2 +-
 sliding_tile_lib.h  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index e4f2f12..5284dab 100644
--- 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++) {
diff --git a/sliding_tile_lib.h b/sliding_tile_lib.h
index 772817e..1b56da4 100644
--- a/sliding_tile_lib.h
+++ b/sliding_tile_lib.h
@@ -30,7 +30,7 @@ std::ostream& operator<<(std::ostream& os, const Board& board);
 struct Step {
   Board board;
   std::shared_ptr<Step> prev;
-  std::vector<Step*> successors(std::shared_ptr<Step> shared_this);
+  std::vector<Step*> successors(std::shared_ptr<Step> shared_this) const;
   static signed char adjacent[BOARD_SIZE][5];
 };
 std::ostream& operator<<(std::ostream& os, const Step& step);
-- 
2.44.1