Mark const methods const.

diff --git a/sliding_tile_lib.cc b/sliding_tile_lib.cc
index b8ddc154a1a829e3ce7843678c34901334ef7ddf..5b2e798472d08e4b45f547461b71ff135fe787f5 100644 (file)
--- a/sliding_tile_lib.cc
+++ b/sliding_tile_lib.cc
@@ -22,7 +22,7 @@ signed char adjacent[BOARD_SIZE][5] = {
   11,  14,  -1,  -1,  -1,
 };
 
-bool Board::is_valid() {
+bool Board::is_valid() const {
   bool seen[BOARD_SIZE];
   for (int i = 0; i < BOARD_SIZE; i++) {
     seen[i] = false;
@@ -65,7 +65,7 @@ std::istream& operator>>(std::istream& is, Board& board) {
   return is;
 }
 
-signed char Board::hole() {
+signed char Board::hole() const {
   for (int i = 0; i < BOARD_SIZE; i++) {
     if (board[i] == 0) {
       return i;

diff --git a/sliding_tile_lib.h b/sliding_tile_lib.h
index 84d422e2faaf09d44c663a253c1cc02c94418cb1..4d6c0151e45d622c05e3a0ed98a528bbf80405c5 100644 (file)
--- a/sliding_tile_lib.h
+++ b/sliding_tile_lib.h
@@ -8,8 +8,8 @@ const int BOARD_SIZE = BOARD_DIM * BOARD_DIM;
 
 struct Board {
   signed char board[BOARD_SIZE];
-  bool is_valid();
-  signed char hole();
+  bool is_valid() const;
+  signed char hole() const;
 };
 std::istream& operator>>(std::istream& is, Board& board);