get frame score

includes/game.h

@@ -9,6 +9,7 @@ class Game {
 public:
   void roll(int pins);
   int score() const;
+  int frameScore(int frame) const;
 };
 
 #endif

sources/game.cpp

@@ -47,4 +47,37 @@ int Game::score() const {
   }
 
   return total;
+}
+
+int Game::frameScore(int frame) const {
+  int rollIndex = 0;
+
+  for (int f = 1; f < frame; ++f) {
+    if (rollIndex >= rolls.size())
+      return 0;
+    if (rolls[rollIndex] == 10)
+      rollIndex += 1;
+    else
+      rollIndex += 2;
+  }
+
+  if (rollIndex >= rolls.size())
+    return 0;
+
+  if (rolls[rollIndex] == 10) {
+    if (rollIndex + 2 >= rolls.size())
+      return 0;
+    return 10 + rolls[rollIndex + 1] + rolls[rollIndex + 2];
+  }
+
+  if (rollIndex + 1 >= rolls.size())
+    return 0;
+
+  if (rolls[rollIndex] + rolls[rollIndex + 1] == 10) {
+    if (rollIndex + 2 >= rolls.size())
+      return 0;
+    return 10 + rolls[rollIndex + 2];
+  }
+
+  return rolls[rollIndex] + rolls[rollIndex + 1];
 }

tests/test_game.cpp

@@ -108,4 +108,81 @@ TEST(GameTest, ScoreWithStrike) {
   EXPECT_EQ(game.score(), 0);
   game.roll(4);
   EXPECT_EQ(game.score(), 24);
+}
+
+TEST(GameTest, SecondFrameScore) {
+  Game game;
+  game.roll(0);
+  game.roll(2);
+  game.roll(3);
+  game.roll(5);
+  for (int i = 0; i < 16; ++i)
+    game.roll(0);
+  EXPECT_EQ(game.frameScore(2), 8);
+}
+
+TEST(GameTest, FrameScoreWithStrike) {
+  Game game;
+  game.roll(10);
+  game.roll(5);
+  game.roll(4);
+
+  for (int i = 0; i < 17; ++i)
+    game.roll(0);
+  EXPECT_EQ(game.frameScore(1), 19);
+}
+
+TEST(GameTest, FrameScoreWithSpare) {
+  Game game;
+  game.roll(6);
+  game.roll(4);
+  game.roll(5);
+  for (int i = 0; i < 17; ++i)
+    game.roll(0);
+  EXPECT_EQ(game.frameScore(1), 15);
+}
+
+TEST(GameTest, FrameScoreOfTenthFrameWithStrike) {
+  Game game;
+  for (int i = 0; i < 18; ++i)
+    game.roll(0);
+  game.roll(10);
+  game.roll(4);
+  game.roll(3);
+  EXPECT_EQ(game.frameScore(10), 17);
+}
+
+TEST(GameTest, FrameScoreOfTenthFrameWithSpare) {
+  Game game;
+  for (int i = 0; i < 18; ++i)
+    game.roll(0);
+  game.roll(6);
+  game.roll(4);
+  game.roll(3);
+  EXPECT_EQ(game.frameScore(10), 13);
+}
+
+TEST(GameTest, FrameScoreOfTenthFrame) {
+  Game game;
+  for (int i = 0; i < 18; ++i)
+    game.roll(0);
+  game.roll(4);
+  game.roll(4);
+  EXPECT_EQ(game.frameScore(10), 8);
+}
+
+TEST(GameTest, FrameScoreAfterStrike) {
+  Game game;
+  game.roll(10);
+  game.roll(2);
+  game.roll(3);
+  EXPECT_EQ(game.frameScore(2), 5);
+}
+
+TEST(GameTest, FrameScoreTenthFrameIncomplete) {
+  Game game;
+  for (int i = 0; i < 18; ++i)
+    game.roll(0);
+  game.roll(10);
+  EXPECT_EQ(game.frameScore(10), 0);
 }