Bowling C++ Kata

Overview

This kata complements Clean Code: Fundamentals, Ep. 5 - Form.

In bowling, a player rolls a ball down a lane and tries to knock down as many pins as possible. The game consists of ten frames, and in each frame, the player has two opportunities (called rolls) to knock down as many pins as possible.

If, after two rolls, at least one pin is still standing, it’s called an open frame. The score for the frame is the total number of pins knocked down, plus bonus points awarded for strikes or spares.

A spare is when the player knocks down all the pins in two rolls. If the player gets a spare, the score for the frame is ten, plus the number of pins knocked down on their next roll. If a spare is thrown in the tenth frame, the player is awarded one more roll.

A strike is when the player knocks down all the pins in one roll. If the player gets a strike, their score for the frame is ten, plus the number of pins knocked down on their next two rolls. If a strike is thrown in the tenth frame, the player is awarded two more rolls.

The final score is the total of all frame scores.

Instructions

In this kata, you will write a class BowlingGame that calculates the score of a game of ten-pin bowling with two methods:

1. void roll(int pins) is called each time the player rolls a ball, with pins representing the number of pins knocked down in the current roll;
2. int score() returns the score calculated using the above rules.

Examples

Spare with a bonus

Here is an example of a game where the player gets a bonus after rolling a spare:

game.roll(7);
game.roll(3);  // Spare: 7 + 3 + 6 (bonus) = 16
game.roll(6);
game.roll(2);  // Open frame: 6 + 2 = 8

assert(game.score() == 24);

In this example, the player got a spare, which is ten plus the next roll. The next roll (from the second frame) was a 6, so the value of the first frame is 16. The second frame is worth exactly the number of pins the player knocked down. Added to 16, it gives a total of 24.

Perfect game

Here is an example of a game where the player gets the maximum score:

for (int i = 0; i < 12; ++i)
    game.roll(10);

assert(game.score() == 300);

In this example, the player gets 12 strikes in a row, the maximum number of strikes possible in a game. Each strike is worth 10 points, plus the pins were knocked down on the next two rolls, resulting in 300 points.

Usage

You can import this project into Replit, and it will handle all dependencies automatically.

Prerequisites

• CMake 3.19+
• Ninja
• GTest

Build

make

Run main

make run

Run tests

make test