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Blackjack

Blackjack

Learning Exercise

Introduction

Like other languages, Go also provides a switch statement. Switch statements are a shorter way to write long if ... else if statements. To make a switch, we start by using the keyword switch followed by a value or expression. We then declare each one of the conditions with the case keyword. We can also declare a default case, that will run when none of the previous case conditions matched:

operatingSystem := "windows"

switch operatingSystem {
case "windows":
    // do something if the operating system is windows
case "linux":
    // do something if the operating system is linux
case "macos":
    // do something if the operating system is macos
default:
    // do something if the operating system is none of the above
} 

One interesting thing about switch statements, is that the value after the switch keyword can be omitted, and we can have boolean conditions for each case:

age := 21

switch {
case age > 20 && age < 30:
    // do something if age is between 20 and 30
case age == 10:
    // do something if age is equal to 10
default:
    // do something else for every other case
}

Instructions

In this exercise we will simulate the first turn of a Blackjack game.

You will receive two cards and will be able to see the face up card of the dealer. All cards are represented using a string such as "ace", "king", "three", "two", etc. The values of each card are:

card value card value
ace 11 eight 8
two 2 nine 9
three 3 ten 10
four 4 jack 10
five 5 queen 10
six 6 king 10
seven 7 other 0

Note: Commonly, aces can take the value of 1 or 11 but for simplicity we will assume that they can only take the value of 11.

Depending on your two cards and the card of the dealer, there is a strategy for the first turn of the game, in which you have the following options:

  • Stand (S)
  • Hit (H)
  • Split (P)
  • Automatically win (W)

Although not optimal yet, you will follow the strategy your friend Alex has been developing, which is as follows:

  • If you have a pair of aces you must always split them.
  • If you have a Blackjack (two cards that sum up to a value of 21), and the dealer does not have an ace, a figure or a ten then you automatically win. If the dealer does have any of those cards then you'll have to stand and wait for the reveal of the other card.
  • If your cards sum up to a value within the range [17, 20] you should always stand.
  • If your cards sum up to a value within the range [12, 16] you should always stand unless the dealer has a 7 or higher, in which case you should always hit.
  • If your cards sum up to 11 or lower you should always hit.

1. Calculate the value of any given card.

Implement a function to calculate the numerical value of a card:

value := ParseCard("ace")
fmt.Println(value)
// Output: 11

2. Implement the decision logic for the first turn.

Write a function that implements the decision logic as described above:

func FirstTurn(card1, card2, dealerCard string) string

Here are some examples for the expected outcomes:

FirstTurn("ace", "ace", "jack") == "P"
FirstTurn("ace", "king", "ace") == "S"
FirstTurn("five", "queen", "ace") == "H"
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