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artemkorsakov's solution

to Beer Song in the C# Track

Published at Feb 25 2019 · 0 comments
Instructions
Test suite
Solution

Recite the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.

Note that not all verses are identical.

99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.

98 bottles of beer on the wall, 98 bottles of beer.
Take one down and pass it around, 97 bottles of beer on the wall.

97 bottles of beer on the wall, 97 bottles of beer.
Take one down and pass it around, 96 bottles of beer on the wall.

96 bottles of beer on the wall, 96 bottles of beer.
Take one down and pass it around, 95 bottles of beer on the wall.

95 bottles of beer on the wall, 95 bottles of beer.
Take one down and pass it around, 94 bottles of beer on the wall.

94 bottles of beer on the wall, 94 bottles of beer.
Take one down and pass it around, 93 bottles of beer on the wall.

93 bottles of beer on the wall, 93 bottles of beer.
Take one down and pass it around, 92 bottles of beer on the wall.

92 bottles of beer on the wall, 92 bottles of beer.
Take one down and pass it around, 91 bottles of beer on the wall.

91 bottles of beer on the wall, 91 bottles of beer.
Take one down and pass it around, 90 bottles of beer on the wall.

90 bottles of beer on the wall, 90 bottles of beer.
Take one down and pass it around, 89 bottles of beer on the wall.

89 bottles of beer on the wall, 89 bottles of beer.
Take one down and pass it around, 88 bottles of beer on the wall.

88 bottles of beer on the wall, 88 bottles of beer.
Take one down and pass it around, 87 bottles of beer on the wall.

87 bottles of beer on the wall, 87 bottles of beer.
Take one down and pass it around, 86 bottles of beer on the wall.

86 bottles of beer on the wall, 86 bottles of beer.
Take one down and pass it around, 85 bottles of beer on the wall.

85 bottles of beer on the wall, 85 bottles of beer.
Take one down and pass it around, 84 bottles of beer on the wall.

84 bottles of beer on the wall, 84 bottles of beer.
Take one down and pass it around, 83 bottles of beer on the wall.

83 bottles of beer on the wall, 83 bottles of beer.
Take one down and pass it around, 82 bottles of beer on the wall.

82 bottles of beer on the wall, 82 bottles of beer.
Take one down and pass it around, 81 bottles of beer on the wall.

81 bottles of beer on the wall, 81 bottles of beer.
Take one down and pass it around, 80 bottles of beer on the wall.

80 bottles of beer on the wall, 80 bottles of beer.
Take one down and pass it around, 79 bottles of beer on the wall.

79 bottles of beer on the wall, 79 bottles of beer.
Take one down and pass it around, 78 bottles of beer on the wall.

78 bottles of beer on the wall, 78 bottles of beer.
Take one down and pass it around, 77 bottles of beer on the wall.

77 bottles of beer on the wall, 77 bottles of beer.
Take one down and pass it around, 76 bottles of beer on the wall.

76 bottles of beer on the wall, 76 bottles of beer.
Take one down and pass it around, 75 bottles of beer on the wall.

75 bottles of beer on the wall, 75 bottles of beer.
Take one down and pass it around, 74 bottles of beer on the wall.

74 bottles of beer on the wall, 74 bottles of beer.
Take one down and pass it around, 73 bottles of beer on the wall.

73 bottles of beer on the wall, 73 bottles of beer.
Take one down and pass it around, 72 bottles of beer on the wall.

72 bottles of beer on the wall, 72 bottles of beer.
Take one down and pass it around, 71 bottles of beer on the wall.

71 bottles of beer on the wall, 71 bottles of beer.
Take one down and pass it around, 70 bottles of beer on the wall.

70 bottles of beer on the wall, 70 bottles of beer.
Take one down and pass it around, 69 bottles of beer on the wall.

69 bottles of beer on the wall, 69 bottles of beer.
Take one down and pass it around, 68 bottles of beer on the wall.

68 bottles of beer on the wall, 68 bottles of beer.
Take one down and pass it around, 67 bottles of beer on the wall.

67 bottles of beer on the wall, 67 bottles of beer.
Take one down and pass it around, 66 bottles of beer on the wall.

66 bottles of beer on the wall, 66 bottles of beer.
Take one down and pass it around, 65 bottles of beer on the wall.

65 bottles of beer on the wall, 65 bottles of beer.
Take one down and pass it around, 64 bottles of beer on the wall.

64 bottles of beer on the wall, 64 bottles of beer.
Take one down and pass it around, 63 bottles of beer on the wall.

63 bottles of beer on the wall, 63 bottles of beer.
Take one down and pass it around, 62 bottles of beer on the wall.

62 bottles of beer on the wall, 62 bottles of beer.
Take one down and pass it around, 61 bottles of beer on the wall.

61 bottles of beer on the wall, 61 bottles of beer.
Take one down and pass it around, 60 bottles of beer on the wall.

60 bottles of beer on the wall, 60 bottles of beer.
Take one down and pass it around, 59 bottles of beer on the wall.

59 bottles of beer on the wall, 59 bottles of beer.
Take one down and pass it around, 58 bottles of beer on the wall.

58 bottles of beer on the wall, 58 bottles of beer.
Take one down and pass it around, 57 bottles of beer on the wall.

57 bottles of beer on the wall, 57 bottles of beer.
Take one down and pass it around, 56 bottles of beer on the wall.

56 bottles of beer on the wall, 56 bottles of beer.
Take one down and pass it around, 55 bottles of beer on the wall.

55 bottles of beer on the wall, 55 bottles of beer.
Take one down and pass it around, 54 bottles of beer on the wall.

54 bottles of beer on the wall, 54 bottles of beer.
Take one down and pass it around, 53 bottles of beer on the wall.

53 bottles of beer on the wall, 53 bottles of beer.
Take one down and pass it around, 52 bottles of beer on the wall.

52 bottles of beer on the wall, 52 bottles of beer.
Take one down and pass it around, 51 bottles of beer on the wall.

51 bottles of beer on the wall, 51 bottles of beer.
Take one down and pass it around, 50 bottles of beer on the wall.

50 bottles of beer on the wall, 50 bottles of beer.
Take one down and pass it around, 49 bottles of beer on the wall.

49 bottles of beer on the wall, 49 bottles of beer.
Take one down and pass it around, 48 bottles of beer on the wall.

48 bottles of beer on the wall, 48 bottles of beer.
Take one down and pass it around, 47 bottles of beer on the wall.

47 bottles of beer on the wall, 47 bottles of beer.
Take one down and pass it around, 46 bottles of beer on the wall.

46 bottles of beer on the wall, 46 bottles of beer.
Take one down and pass it around, 45 bottles of beer on the wall.

45 bottles of beer on the wall, 45 bottles of beer.
Take one down and pass it around, 44 bottles of beer on the wall.

44 bottles of beer on the wall, 44 bottles of beer.
Take one down and pass it around, 43 bottles of beer on the wall.

43 bottles of beer on the wall, 43 bottles of beer.
Take one down and pass it around, 42 bottles of beer on the wall.

42 bottles of beer on the wall, 42 bottles of beer.
Take one down and pass it around, 41 bottles of beer on the wall.

41 bottles of beer on the wall, 41 bottles of beer.
Take one down and pass it around, 40 bottles of beer on the wall.

40 bottles of beer on the wall, 40 bottles of beer.
Take one down and pass it around, 39 bottles of beer on the wall.

39 bottles of beer on the wall, 39 bottles of beer.
Take one down and pass it around, 38 bottles of beer on the wall.

38 bottles of beer on the wall, 38 bottles of beer.
Take one down and pass it around, 37 bottles of beer on the wall.

37 bottles of beer on the wall, 37 bottles of beer.
Take one down and pass it around, 36 bottles of beer on the wall.

36 bottles of beer on the wall, 36 bottles of beer.
Take one down and pass it around, 35 bottles of beer on the wall.

35 bottles of beer on the wall, 35 bottles of beer.
Take one down and pass it around, 34 bottles of beer on the wall.

34 bottles of beer on the wall, 34 bottles of beer.
Take one down and pass it around, 33 bottles of beer on the wall.

33 bottles of beer on the wall, 33 bottles of beer.
Take one down and pass it around, 32 bottles of beer on the wall.

32 bottles of beer on the wall, 32 bottles of beer.
Take one down and pass it around, 31 bottles of beer on the wall.

31 bottles of beer on the wall, 31 bottles of beer.
Take one down and pass it around, 30 bottles of beer on the wall.

30 bottles of beer on the wall, 30 bottles of beer.
Take one down and pass it around, 29 bottles of beer on the wall.

29 bottles of beer on the wall, 29 bottles of beer.
Take one down and pass it around, 28 bottles of beer on the wall.

28 bottles of beer on the wall, 28 bottles of beer.
Take one down and pass it around, 27 bottles of beer on the wall.

27 bottles of beer on the wall, 27 bottles of beer.
Take one down and pass it around, 26 bottles of beer on the wall.

26 bottles of beer on the wall, 26 bottles of beer.
Take one down and pass it around, 25 bottles of beer on the wall.

25 bottles of beer on the wall, 25 bottles of beer.
Take one down and pass it around, 24 bottles of beer on the wall.

24 bottles of beer on the wall, 24 bottles of beer.
Take one down and pass it around, 23 bottles of beer on the wall.

23 bottles of beer on the wall, 23 bottles of beer.
Take one down and pass it around, 22 bottles of beer on the wall.

22 bottles of beer on the wall, 22 bottles of beer.
Take one down and pass it around, 21 bottles of beer on the wall.

21 bottles of beer on the wall, 21 bottles of beer.
Take one down and pass it around, 20 bottles of beer on the wall.

20 bottles of beer on the wall, 20 bottles of beer.
Take one down and pass it around, 19 bottles of beer on the wall.

19 bottles of beer on the wall, 19 bottles of beer.
Take one down and pass it around, 18 bottles of beer on the wall.

18 bottles of beer on the wall, 18 bottles of beer.
Take one down and pass it around, 17 bottles of beer on the wall.

17 bottles of beer on the wall, 17 bottles of beer.
Take one down and pass it around, 16 bottles of beer on the wall.

16 bottles of beer on the wall, 16 bottles of beer.
Take one down and pass it around, 15 bottles of beer on the wall.

15 bottles of beer on the wall, 15 bottles of beer.
Take one down and pass it around, 14 bottles of beer on the wall.

14 bottles of beer on the wall, 14 bottles of beer.
Take one down and pass it around, 13 bottles of beer on the wall.

13 bottles of beer on the wall, 13 bottles of beer.
Take one down and pass it around, 12 bottles of beer on the wall.

12 bottles of beer on the wall, 12 bottles of beer.
Take one down and pass it around, 11 bottles of beer on the wall.

11 bottles of beer on the wall, 11 bottles of beer.
Take one down and pass it around, 10 bottles of beer on the wall.

10 bottles of beer on the wall, 10 bottles of beer.
Take one down and pass it around, 9 bottles of beer on the wall.

9 bottles of beer on the wall, 9 bottles of beer.
Take one down and pass it around, 8 bottles of beer on the wall.

8 bottles of beer on the wall, 8 bottles of beer.
Take one down and pass it around, 7 bottles of beer on the wall.

7 bottles of beer on the wall, 7 bottles of beer.
Take one down and pass it around, 6 bottles of beer on the wall.

6 bottles of beer on the wall, 6 bottles of beer.
Take one down and pass it around, 5 bottles of beer on the wall.

5 bottles of beer on the wall, 5 bottles of beer.
Take one down and pass it around, 4 bottles of beer on the wall.

4 bottles of beer on the wall, 4 bottles of beer.
Take one down and pass it around, 3 bottles of beer on the wall.

3 bottles of beer on the wall, 3 bottles of beer.
Take one down and pass it around, 2 bottles of beer on the wall.

2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.

1 bottle of beer on the wall, 1 bottle of beer.
Take it down and pass it around, no more bottles of beer on the wall.

No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.

For bonus points

Did you get the tests passing and the code clean? If you want to, these are some additional things you could try:

  • Remove as much duplication as you possibly can.
  • Optimize for readability, even if it means introducing duplication.
  • If you've removed all the duplication, do you have a lot of conditionals? Try replacing the conditionals with polymorphism, if it applies in this language. How readable is it?

Then please share your thoughts in a comment on the submission. Did this experiment make the code better? Worse? Did you learn anything from it?

Hints

  • Try to capture the structure of the song in your code, where you build up the song by composing its parts.

Running the tests

To run the tests, run the command dotnet test from within the exercise directory.

Initially, only the first test will be enabled. This is to encourage you to solve the exercise one step at a time. Once you get the first test passing, remove the Skip property from the next test and work on getting that test passing. Once none of the tests are skipped and they are all passing, you can submit your solution using exercism submit BeerSong.cs

Further information

For more detailed information about the C# track, including how to get help if you're having trouble, please visit the exercism.io C# language page.

Source

Learn to Program by Chris Pine http://pine.fm/LearnToProgram/?Chapter=06

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

BeerSongTest.cs

// This file was auto-generated based on version 2.1.0 of the canonical data.

using Xunit;

public class BeerSongTest
{
    [Fact]
    public void First_generic_verse()
    {
        var expected = 
            "99 bottles of beer on the wall, 99 bottles of beer.\n" +
            "Take one down and pass it around, 98 bottles of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(99, 1));
    }

    [Fact(Skip = "Remove to run test")]
    public void Last_generic_verse()
    {
        var expected = 
            "3 bottles of beer on the wall, 3 bottles of beer.\n" +
            "Take one down and pass it around, 2 bottles of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(3, 1));
    }

    [Fact(Skip = "Remove to run test")]
    public void Verse_with_2_bottles()
    {
        var expected = 
            "2 bottles of beer on the wall, 2 bottles of beer.\n" +
            "Take one down and pass it around, 1 bottle of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(2, 1));
    }

    [Fact(Skip = "Remove to run test")]
    public void Verse_with_1_bottle()
    {
        var expected = 
            "1 bottle of beer on the wall, 1 bottle of beer.\n" +
            "Take it down and pass it around, no more bottles of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(1, 1));
    }

    [Fact(Skip = "Remove to run test")]
    public void Verse_with_0_bottles()
    {
        var expected = 
            "No more bottles of beer on the wall, no more bottles of beer.\n" +
            "Go to the store and buy some more, 99 bottles of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(0, 1));
    }

    [Fact(Skip = "Remove to run test")]
    public void First_two_verses()
    {
        var expected = 
            "99 bottles of beer on the wall, 99 bottles of beer.\n" +
            "Take one down and pass it around, 98 bottles of beer on the wall.\n" +
            "\n" +
            "98 bottles of beer on the wall, 98 bottles of beer.\n" +
            "Take one down and pass it around, 97 bottles of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(99, 2));
    }

    [Fact(Skip = "Remove to run test")]
    public void Last_three_verses()
    {
        var expected = 
            "2 bottles of beer on the wall, 2 bottles of beer.\n" +
            "Take one down and pass it around, 1 bottle of beer on the wall.\n" +
            "\n" +
            "1 bottle of beer on the wall, 1 bottle of beer.\n" +
            "Take it down and pass it around, no more bottles of beer on the wall.\n" +
            "\n" +
            "No more bottles of beer on the wall, no more bottles of beer.\n" +
            "Go to the store and buy some more, 99 bottles of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(2, 3));
    }

    [Fact(Skip = "Remove to run test")]
    public void All_verses()
    {
        var expected = 
            "99 bottles of beer on the wall, 99 bottles of beer.\n" +
            "Take one down and pass it around, 98 bottles of beer on the wall.\n" +
            "\n" +
            "98 bottles of beer on the wall, 98 bottles of beer.\n" +
            "Take one down and pass it around, 97 bottles of beer on the wall.\n" +
            "\n" +
            "97 bottles of beer on the wall, 97 bottles of beer.\n" +
            "Take one down and pass it around, 96 bottles of beer on the wall.\n" +
            "\n" +
            "96 bottles of beer on the wall, 96 bottles of beer.\n" +
            "Take one down and pass it around, 95 bottles of beer on the wall.\n" +
            "\n" +
            "95 bottles of beer on the wall, 95 bottles of beer.\n" +
            "Take one down and pass it around, 94 bottles of beer on the wall.\n" +
            "\n" +
            "94 bottles of beer on the wall, 94 bottles of beer.\n" +
            "Take one down and pass it around, 93 bottles of beer on the wall.\n" +
            "\n" +
            "93 bottles of beer on the wall, 93 bottles of beer.\n" +
            "Take one down and pass it around, 92 bottles of beer on the wall.\n" +
            "\n" +
            "92 bottles of beer on the wall, 92 bottles of beer.\n" +
            "Take one down and pass it around, 91 bottles of beer on the wall.\n" +
            "\n" +
            "91 bottles of beer on the wall, 91 bottles of beer.\n" +
            "Take one down and pass it around, 90 bottles of beer on the wall.\n" +
            "\n" +
            "90 bottles of beer on the wall, 90 bottles of beer.\n" +
            "Take one down and pass it around, 89 bottles of beer on the wall.\n" +
            "\n" +
            "89 bottles of beer on the wall, 89 bottles of beer.\n" +
            "Take one down and pass it around, 88 bottles of beer on the wall.\n" +
            "\n" +
            "88 bottles of beer on the wall, 88 bottles of beer.\n" +
            "Take one down and pass it around, 87 bottles of beer on the wall.\n" +
            "\n" +
            "87 bottles of beer on the wall, 87 bottles of beer.\n" +
            "Take one down and pass it around, 86 bottles of beer on the wall.\n" +
            "\n" +
            "86 bottles of beer on the wall, 86 bottles of beer.\n" +
            "Take one down and pass it around, 85 bottles of beer on the wall.\n" +
            "\n" +
            "85 bottles of beer on the wall, 85 bottles of beer.\n" +
            "Take one down and pass it around, 84 bottles of beer on the wall.\n" +
            "\n" +
            "84 bottles of beer on the wall, 84 bottles of beer.\n" +
            "Take one down and pass it around, 83 bottles of beer on the wall.\n" +
            "\n" +
            "83 bottles of beer on the wall, 83 bottles of beer.\n" +
            "Take one down and pass it around, 82 bottles of beer on the wall.\n" +
            "\n" +
            "82 bottles of beer on the wall, 82 bottles of beer.\n" +
            "Take one down and pass it around, 81 bottles of beer on the wall.\n" +
            "\n" +
            "81 bottles of beer on the wall, 81 bottles of beer.\n" +
            "Take one down and pass it around, 80 bottles of beer on the wall.\n" +
            "\n" +
            "80 bottles of beer on the wall, 80 bottles of beer.\n" +
            "Take one down and pass it around, 79 bottles of beer on the wall.\n" +
            "\n" +
            "79 bottles of beer on the wall, 79 bottles of beer.\n" +
            "Take one down and pass it around, 78 bottles of beer on the wall.\n" +
            "\n" +
            "78 bottles of beer on the wall, 78 bottles of beer.\n" +
            "Take one down and pass it around, 77 bottles of beer on the wall.\n" +
            "\n" +
            "77 bottles of beer on the wall, 77 bottles of beer.\n" +
            "Take one down and pass it around, 76 bottles of beer on the wall.\n" +
            "\n" +
            "76 bottles of beer on the wall, 76 bottles of beer.\n" +
            "Take one down and pass it around, 75 bottles of beer on the wall.\n" +
            "\n" +
            "75 bottles of beer on the wall, 75 bottles of beer.\n" +
            "Take one down and pass it around, 74 bottles of beer on the wall.\n" +
            "\n" +
            "74 bottles of beer on the wall, 74 bottles of beer.\n" +
            "Take one down and pass it around, 73 bottles of beer on the wall.\n" +
            "\n" +
            "73 bottles of beer on the wall, 73 bottles of beer.\n" +
            "Take one down and pass it around, 72 bottles of beer on the wall.\n" +
            "\n" +
            "72 bottles of beer on the wall, 72 bottles of beer.\n" +
            "Take one down and pass it around, 71 bottles of beer on the wall.\n" +
            "\n" +
            "71 bottles of beer on the wall, 71 bottles of beer.\n" +
            "Take one down and pass it around, 70 bottles of beer on the wall.\n" +
            "\n" +
            "70 bottles of beer on the wall, 70 bottles of beer.\n" +
            "Take one down and pass it around, 69 bottles of beer on the wall.\n" +
            "\n" +
            "69 bottles of beer on the wall, 69 bottles of beer.\n" +
            "Take one down and pass it around, 68 bottles of beer on the wall.\n" +
            "\n" +
            "68 bottles of beer on the wall, 68 bottles of beer.\n" +
            "Take one down and pass it around, 67 bottles of beer on the wall.\n" +
            "\n" +
            "67 bottles of beer on the wall, 67 bottles of beer.\n" +
            "Take one down and pass it around, 66 bottles of beer on the wall.\n" +
            "\n" +
            "66 bottles of beer on the wall, 66 bottles of beer.\n" +
            "Take one down and pass it around, 65 bottles of beer on the wall.\n" +
            "\n" +
            "65 bottles of beer on the wall, 65 bottles of beer.\n" +
            "Take one down and pass it around, 64 bottles of beer on the wall.\n" +
            "\n" +
            "64 bottles of beer on the wall, 64 bottles of beer.\n" +
            "Take one down and pass it around, 63 bottles of beer on the wall.\n" +
            "\n" +
            "63 bottles of beer on the wall, 63 bottles of beer.\n" +
            "Take one down and pass it around, 62 bottles of beer on the wall.\n" +
            "\n" +
            "62 bottles of beer on the wall, 62 bottles of beer.\n" +
            "Take one down and pass it around, 61 bottles of beer on the wall.\n" +
            "\n" +
            "61 bottles of beer on the wall, 61 bottles of beer.\n" +
            "Take one down and pass it around, 60 bottles of beer on the wall.\n" +
            "\n" +
            "60 bottles of beer on the wall, 60 bottles of beer.\n" +
            "Take one down and pass it around, 59 bottles of beer on the wall.\n" +
            "\n" +
            "59 bottles of beer on the wall, 59 bottles of beer.\n" +
            "Take one down and pass it around, 58 bottles of beer on the wall.\n" +
            "\n" +
            "58 bottles of beer on the wall, 58 bottles of beer.\n" +
            "Take one down and pass it around, 57 bottles of beer on the wall.\n" +
            "\n" +
            "57 bottles of beer on the wall, 57 bottles of beer.\n" +
            "Take one down and pass it around, 56 bottles of beer on the wall.\n" +
            "\n" +
            "56 bottles of beer on the wall, 56 bottles of beer.\n" +
            "Take one down and pass it around, 55 bottles of beer on the wall.\n" +
            "\n" +
            "55 bottles of beer on the wall, 55 bottles of beer.\n" +
            "Take one down and pass it around, 54 bottles of beer on the wall.\n" +
            "\n" +
            "54 bottles of beer on the wall, 54 bottles of beer.\n" +
            "Take one down and pass it around, 53 bottles of beer on the wall.\n" +
            "\n" +
            "53 bottles of beer on the wall, 53 bottles of beer.\n" +
            "Take one down and pass it around, 52 bottles of beer on the wall.\n" +
            "\n" +
            "52 bottles of beer on the wall, 52 bottles of beer.\n" +
            "Take one down and pass it around, 51 bottles of beer on the wall.\n" +
            "\n" +
            "51 bottles of beer on the wall, 51 bottles of beer.\n" +
            "Take one down and pass it around, 50 bottles of beer on the wall.\n" +
            "\n" +
            "50 bottles of beer on the wall, 50 bottles of beer.\n" +
            "Take one down and pass it around, 49 bottles of beer on the wall.\n" +
            "\n" +
            "49 bottles of beer on the wall, 49 bottles of beer.\n" +
            "Take one down and pass it around, 48 bottles of beer on the wall.\n" +
            "\n" +
            "48 bottles of beer on the wall, 48 bottles of beer.\n" +
            "Take one down and pass it around, 47 bottles of beer on the wall.\n" +
            "\n" +
            "47 bottles of beer on the wall, 47 bottles of beer.\n" +
            "Take one down and pass it around, 46 bottles of beer on the wall.\n" +
            "\n" +
            "46 bottles of beer on the wall, 46 bottles of beer.\n" +
            "Take one down and pass it around, 45 bottles of beer on the wall.\n" +
            "\n" +
            "45 bottles of beer on the wall, 45 bottles of beer.\n" +
            "Take one down and pass it around, 44 bottles of beer on the wall.\n" +
            "\n" +
            "44 bottles of beer on the wall, 44 bottles of beer.\n" +
            "Take one down and pass it around, 43 bottles of beer on the wall.\n" +
            "\n" +
            "43 bottles of beer on the wall, 43 bottles of beer.\n" +
            "Take one down and pass it around, 42 bottles of beer on the wall.\n" +
            "\n" +
            "42 bottles of beer on the wall, 42 bottles of beer.\n" +
            "Take one down and pass it around, 41 bottles of beer on the wall.\n" +
            "\n" +
            "41 bottles of beer on the wall, 41 bottles of beer.\n" +
            "Take one down and pass it around, 40 bottles of beer on the wall.\n" +
            "\n" +
            "40 bottles of beer on the wall, 40 bottles of beer.\n" +
            "Take one down and pass it around, 39 bottles of beer on the wall.\n" +
            "\n" +
            "39 bottles of beer on the wall, 39 bottles of beer.\n" +
            "Take one down and pass it around, 38 bottles of beer on the wall.\n" +
            "\n" +
            "38 bottles of beer on the wall, 38 bottles of beer.\n" +
            "Take one down and pass it around, 37 bottles of beer on the wall.\n" +
            "\n" +
            "37 bottles of beer on the wall, 37 bottles of beer.\n" +
            "Take one down and pass it around, 36 bottles of beer on the wall.\n" +
            "\n" +
            "36 bottles of beer on the wall, 36 bottles of beer.\n" +
            "Take one down and pass it around, 35 bottles of beer on the wall.\n" +
            "\n" +
            "35 bottles of beer on the wall, 35 bottles of beer.\n" +
            "Take one down and pass it around, 34 bottles of beer on the wall.\n" +
            "\n" +
            "34 bottles of beer on the wall, 34 bottles of beer.\n" +
            "Take one down and pass it around, 33 bottles of beer on the wall.\n" +
            "\n" +
            "33 bottles of beer on the wall, 33 bottles of beer.\n" +
            "Take one down and pass it around, 32 bottles of beer on the wall.\n" +
            "\n" +
            "32 bottles of beer on the wall, 32 bottles of beer.\n" +
            "Take one down and pass it around, 31 bottles of beer on the wall.\n" +
            "\n" +
            "31 bottles of beer on the wall, 31 bottles of beer.\n" +
            "Take one down and pass it around, 30 bottles of beer on the wall.\n" +
            "\n" +
            "30 bottles of beer on the wall, 30 bottles of beer.\n" +
            "Take one down and pass it around, 29 bottles of beer on the wall.\n" +
            "\n" +
            "29 bottles of beer on the wall, 29 bottles of beer.\n" +
            "Take one down and pass it around, 28 bottles of beer on the wall.\n" +
            "\n" +
            "28 bottles of beer on the wall, 28 bottles of beer.\n" +
            "Take one down and pass it around, 27 bottles of beer on the wall.\n" +
            "\n" +
            "27 bottles of beer on the wall, 27 bottles of beer.\n" +
            "Take one down and pass it around, 26 bottles of beer on the wall.\n" +
            "\n" +
            "26 bottles of beer on the wall, 26 bottles of beer.\n" +
            "Take one down and pass it around, 25 bottles of beer on the wall.\n" +
            "\n" +
            "25 bottles of beer on the wall, 25 bottles of beer.\n" +
            "Take one down and pass it around, 24 bottles of beer on the wall.\n" +
            "\n" +
            "24 bottles of beer on the wall, 24 bottles of beer.\n" +
            "Take one down and pass it around, 23 bottles of beer on the wall.\n" +
            "\n" +
            "23 bottles of beer on the wall, 23 bottles of beer.\n" +
            "Take one down and pass it around, 22 bottles of beer on the wall.\n" +
            "\n" +
            "22 bottles of beer on the wall, 22 bottles of beer.\n" +
            "Take one down and pass it around, 21 bottles of beer on the wall.\n" +
            "\n" +
            "21 bottles of beer on the wall, 21 bottles of beer.\n" +
            "Take one down and pass it around, 20 bottles of beer on the wall.\n" +
            "\n" +
            "20 bottles of beer on the wall, 20 bottles of beer.\n" +
            "Take one down and pass it around, 19 bottles of beer on the wall.\n" +
            "\n" +
            "19 bottles of beer on the wall, 19 bottles of beer.\n" +
            "Take one down and pass it around, 18 bottles of beer on the wall.\n" +
            "\n" +
            "18 bottles of beer on the wall, 18 bottles of beer.\n" +
            "Take one down and pass it around, 17 bottles of beer on the wall.\n" +
            "\n" +
            "17 bottles of beer on the wall, 17 bottles of beer.\n" +
            "Take one down and pass it around, 16 bottles of beer on the wall.\n" +
            "\n" +
            "16 bottles of beer on the wall, 16 bottles of beer.\n" +
            "Take one down and pass it around, 15 bottles of beer on the wall.\n" +
            "\n" +
            "15 bottles of beer on the wall, 15 bottles of beer.\n" +
            "Take one down and pass it around, 14 bottles of beer on the wall.\n" +
            "\n" +
            "14 bottles of beer on the wall, 14 bottles of beer.\n" +
            "Take one down and pass it around, 13 bottles of beer on the wall.\n" +
            "\n" +
            "13 bottles of beer on the wall, 13 bottles of beer.\n" +
            "Take one down and pass it around, 12 bottles of beer on the wall.\n" +
            "\n" +
            "12 bottles of beer on the wall, 12 bottles of beer.\n" +
            "Take one down and pass it around, 11 bottles of beer on the wall.\n" +
            "\n" +
            "11 bottles of beer on the wall, 11 bottles of beer.\n" +
            "Take one down and pass it around, 10 bottles of beer on the wall.\n" +
            "\n" +
            "10 bottles of beer on the wall, 10 bottles of beer.\n" +
            "Take one down and pass it around, 9 bottles of beer on the wall.\n" +
            "\n" +
            "9 bottles of beer on the wall, 9 bottles of beer.\n" +
            "Take one down and pass it around, 8 bottles of beer on the wall.\n" +
            "\n" +
            "8 bottles of beer on the wall, 8 bottles of beer.\n" +
            "Take one down and pass it around, 7 bottles of beer on the wall.\n" +
            "\n" +
            "7 bottles of beer on the wall, 7 bottles of beer.\n" +
            "Take one down and pass it around, 6 bottles of beer on the wall.\n" +
            "\n" +
            "6 bottles of beer on the wall, 6 bottles of beer.\n" +
            "Take one down and pass it around, 5 bottles of beer on the wall.\n" +
            "\n" +
            "5 bottles of beer on the wall, 5 bottles of beer.\n" +
            "Take one down and pass it around, 4 bottles of beer on the wall.\n" +
            "\n" +
            "4 bottles of beer on the wall, 4 bottles of beer.\n" +
            "Take one down and pass it around, 3 bottles of beer on the wall.\n" +
            "\n" +
            "3 bottles of beer on the wall, 3 bottles of beer.\n" +
            "Take one down and pass it around, 2 bottles of beer on the wall.\n" +
            "\n" +
            "2 bottles of beer on the wall, 2 bottles of beer.\n" +
            "Take one down and pass it around, 1 bottle of beer on the wall.\n" +
            "\n" +
            "1 bottle of beer on the wall, 1 bottle of beer.\n" +
            "Take it down and pass it around, no more bottles of beer on the wall.\n" +
            "\n" +
            "No more bottles of beer on the wall, no more bottles of beer.\n" +
            "Go to the store and buy some more, 99 bottles of beer on the wall.";
        Assert.Equal(expected, BeerSong.Recite(99, 100));
    }
}
using System;
using System.Text;

public static class BeerSong
{
    public static string Recite(int startBottles, int takeDown)
    {
        if (startBottles < 0 || takeDown < 0 || startBottles + 1 < takeDown)
        {
            return "";
        }
        var result = new StringBuilder();
        for (var i = 0; i < takeDown; i++)
        {
            var bottle = GetBottles(startBottles - i);
            result.Append(bottle.GetVerse());
            if (i < takeDown - 1)
            {
                result.Append("\n\n");
            }
        }

        return result.ToString();
    }

    private static Bottle GetBottles(int countOfBottles)
    {
        switch (countOfBottles)
        {
            case 0:
                return new NoBottle();
            case 1:
                return new OneBottle();
            case 2:
                return new TwoBottles();
            default:
                return new MoreThanTwoBottles(countOfBottles);
        }
    }

    private abstract class Bottle
    {
        protected abstract string GetFirstLine();

        protected abstract string GetSecondLine();

        internal string GetVerse()
        {
            return GetFirstLine() + GetSecondLine();
        }
    }

    private class NoBottle : Bottle
    {
        protected override string GetFirstLine()
        {
            return "No more bottles of beer on the wall, no more bottles of beer.\n";
        }

        protected override string GetSecondLine()
        {
            return "Go to the store and buy some more, 99 bottles of beer on the wall.";
        }
    }

    private class OneBottle : Bottle
    {
        protected override string GetFirstLine()
        {
            return "1 bottle of beer on the wall, 1 bottle of beer.\n";
        }

        protected override string GetSecondLine()
        {
            return "Take it down and pass it around, no more bottles of beer on the wall.";
        }
    }

    private class TwoBottles : Bottle
    {
        protected override string GetFirstLine()
        {
            return "2 bottles of beer on the wall, 2 bottles of beer.\n";
        }

        protected override string GetSecondLine()
        {
            return "Take one down and pass it around, 1 bottle of beer on the wall.";
        }
    }

    private class MoreThanTwoBottles : Bottle
    {
        private readonly int _countOfBottles;

        internal MoreThanTwoBottles(int countOfBottles)
        {
            _countOfBottles = countOfBottles;
        }

        protected override string GetFirstLine()
        {
            return $"{_countOfBottles} bottles of beer on the wall, {_countOfBottles} bottles of beer.\n";
        }

        protected override string GetSecondLine()
        {
            return $"Take one down and pass it around, {_countOfBottles - 1} bottles of beer on the wall.";
        }
    }
}

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