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to Secret Handshake in the Delphi Pascal Track

Published at Mar 11 2021 · 0 comments
Instructions
Test suite
Solution

There are 10 types of people in the world: Those who understand binary, and those who don't.

You and your fellow cohort of those in the "know" when it comes to binary decide to come up with a secret "handshake".

1 = wink
10 = double blink
100 = close your eyes
1000 = jump


10000 = Reverse the order of the operations in the secret handshake.

Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.

Here's a couple of examples:

Given the input 3, the function would return the array ["wink", "double blink"] because 3 is 11 in binary.

Given the input 19, the function would return the array ["double blink", "wink"] because 19 is 10011 in binary. Notice that the addition of 16 (10000 in binary) has caused the array to be reversed.

Testing

In order to run the tests for this track, you will need to install DUnitX. Please see the installation instructions for more information.

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When Questions Come Up

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For example, if you're submitting ubob.pas for the Bob exercise, the submit command would be something like exercism submit <path_to_exercism_dir>/delphi/bob/ubob.pas.

Source

Bert, in Mary Poppins http://www.imdb.com/title/tt0058331/quotes/qt0437047

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you may request help from a mentor.

uSecretHandshakeTests.pas

unit uSecretHandshakeTests;

interface
uses
  DUnitX.TestFramework;

const
  CanonicalVersion = '1.2.0.1';

type
  [TestFixture]
  SecretHandshakeTest = class(TObject)
  private
    procedure CompareArrays(aExpected, aActual: TArray<string>);
  public
    [Test]
//    [Ignore('Comment the "[Ignore]" statement to run the test')]
    procedure wink_for_1;

    [Test]
    [Ignore]
    procedure double_blink_for_10;

    [Test]
    [Ignore]
    procedure close_your_eyes_for_100;

    [Test]
    [Ignore]
    procedure jump_for_1000;

    [Test]
    [Ignore]
    procedure combine_two_actions;

    [Test]
    [Ignore]
    procedure reverse_two_actions;

    [Test]
    [Ignore]
    procedure reversing_one_action_gives_the_same_action;

    [Test]
    [Ignore]
    procedure reversing_no_actions_still_gives_no_actions;

    [Test]
    [Ignore]
    procedure all_possible_actions;

    [Test]
    [Ignore]
    procedure reverse_all_possible_actions;

    [Test]
    [Ignore]
    procedure do_nothing_for_zero;
  end;

implementation
uses uSecretHandshake;


{ SecretHandshakeTest }

procedure SecretHandshakeTest.all_possible_actions;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 4);
  Expected[0] := 'wink';
  Expected[1] := 'double blink';
  Expected[2] := 'close your eyes';
  Expected[3] := 'jump';

  Actual := TSecretHandshake.commands(15);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.close_your_eyes_for_100;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 1);
  Expected[0] := 'close your eyes';

  Actual := TSecretHandshake.commands(4);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.combine_two_actions;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 2);
  Expected[0] := 'wink';
  Expected[1] := 'double blink';

  Actual := TSecretHandshake.commands(3);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.double_blink_for_10;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 1);
  Expected[0] := 'double blink';

  Actual := TSecretHandshake.commands(2);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.do_nothing_for_zero;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 0);

  Actual := TSecretHandshake.commands(0);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.jump_for_1000;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 1);
  Expected[0] := 'jump';

  Actual := TSecretHandshake.commands(8);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.reverse_all_possible_actions;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 4);
  Expected[0] := 'jump';
  Expected[1] := 'close your eyes';
  Expected[2] := 'double blink';
  Expected[3] := 'wink';

  Actual := TSecretHandshake.commands(31);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.reverse_two_actions;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 2);
  Expected[0] := 'double blink';
  Expected[1] := 'wink';

  Actual := TSecretHandshake.commands(19);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.reversing_no_actions_still_gives_no_actions;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 0);

  Actual := TSecretHandshake.commands(16);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.reversing_one_action_gives_the_same_action;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 1);
  Expected[0] := 'jump';

  Actual := TSecretHandshake.commands(24);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.wink_for_1;
var Expected,
    Actual: TArray<string>;
begin
  SetLength(Expected, 1);
  Expected[0] := 'wink';

  Actual := TSecretHandshake.commands(1);

  CompareArrays(Expected, Actual);
end;

procedure SecretHandshakeTest.CompareArrays(aExpected, aActual: TArray<string>);
var i: integer;
begin
  Assert.AreEqual(length(aExpected), length(aActual));
  for i := Low(aExpected) to High(aExpected) do
    Assert.AreEqual(aExpected[i], aActual[i]);
end;

initialization
  TDUnitX.RegisterTestFixture(SecretHandshakeTest);
end.
unit uSecretHandshake;

interface

type
  TSecretHandshake = class
    private
      class function Reverse(AValue: TArray<String>): TArray<String>;
    public
      class function commands(Avalue: Integer): TArray<String>;
  end;

implementation

uses
  System.SysUtils;

class function TSecretHandshake.commands(AValue: Integer): TArray<String>;
var
  Events: TArray<String>;
  Counter: Integer;
begin
  Events := ['wink'] + ['double blink'] + ['close your eyes'] + ['jump'];
  Counter := 0;
  repeat
    if AValue mod 2 = 1 then
      begin
        if Counter < 4 then
          Result := Result + [Events[Counter]];
        if Counter = 4 then
          Result := Reverse(Result);
      end;
    AValue := AValue div 2;
    Inc(Counter);
  until AValue = 0 ;
end;

class function TSecretHandshake.Reverse(AValue: TArray<String>): TArray<String>;
begin
  Result := [];
  for var I := High(AValue) downto Low(AValue) do
      Result := Result + [AValue[I]];
end;

end.

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