Getting Ready: Online Blackjack Game

Understand the online Blackjack game problem and learn the questions to further simplify this problem.

We'll cover the following

Problem definition
Expectations from the interviewee
Design approach
Design pattern

Problem definition#

Blackjack is one of the most played games in casinos. In this game, several players play against the dealer. The objective of the game is to get closer to 21 than the dealer without exceeding the 21 points. This game is played with a deck of cards. Each card has a specific value associated with it, and these values are compared. The value of an ace card can be 1 or 11 points while cards of 10, Jack, Queen, and King value 10 points. Whereas, cards 2-9 have the same values as the number written on them. Hence, the player having one ace and a face card (King, Queen, or Jack card.) or a 10 card has 21 points. This is called Blackjack.

At the start of the game, a bet is placed by a player, and then the dealer will create hands (Each player and the dealer get two cards each.). All players have both cards exposed while the dealer has one card exposed and one card hidden. Now, both the dealer and the player can hit (Draw an additional card.) a card and ensure that they should not get over 21. Anyone exceeding 21 points, busts and loses the bet. The player can stand pat (Stop taking cards) at any time. When a player stops taking cards, if the player has more points than the dealer but less than 22, they win the bet.

The following slide represents how to play Blackjack:

Blackjack table setup

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The dealer's end and Player's end

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Blackjack case represents if the player's first two cards' sum is equal to 21

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The dealer deals two cards to themselves, one card facing up and the other card facing down

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The dealer will deal two cards to player (both cards facing up)

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Player wins the game because their first two cards' sum is equal to 21 and gets 150 percent profit

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Dealer wins if the dealer card sum is greater than player's card sum

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The dealer deals two cards to themselves and two cards to the player

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The player hits and draws an additional card (8)

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After the player stands, the dealer exposes their second card

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Player loses the game and the bet because player cards' sum (18) is less than dealer cards' sum (19)

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The game results in a draw if the player card sum is equal to the dealer card sum

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The dealer deals two cards to themselves and two cards to the player

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The player hits and draws an additional card (8)

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After the player stands, the dealer exposes their second card

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The game results in a draw because player cards' sum (18) is equal to the dealer cards' sum (18)

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The player wins if their card sum is greater than the dealer card sum

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The dealer deals two cards to themselves and two cards to the player

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The player hits and draws an additional card (8)

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The player wins the game and the bet( 100%) because player cards sum is greater than the dealer cards sum

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Expectations from the interviewee#

There are several components in a Blackjack game, each with specific constraints and requirements placed on them. The following provides an overview of some of the main expectations that the interviewer will want to hear you discuss in more detail during the interview.

Players in the game#

To get a better understanding of the game and the players of the game, you may ask the interviewer the following set of questions:

How many players can play Blackjack?
Can players play the game against each other?

Point dynamics#

The rules related to the number of points also need to be clarified by the interviewer, therefore, you may ask questions listed below:

Upto how many points can the player or the dealer hit the card?
What will happen if the dealer and the player both get the same points?

Card limit#

The interviewer would expect you to ask a question related to the maximum number of cards the player can have. Therefore, you may ask a question listed below:

Is there a limit on the number of cards the player take?

Design approach#

We are going to design this Blackjack game system using the bottom-up design approach. For this purpose, we will follow the steps below:

Identify and design the smallest components first–the card, and player.
Use these small components to design bigger components, for example, the deck and controller.
Repeat the steps above until we design the whole Blackjack game.

Design pattern #

During an interview, it is always a good practice to discuss the design patterns that a parking lot system falls under. Stating the design patterns gives the interviewer a positive impression and shows that the interviewee is well-versed in the advanced concepts of object-oriented design.

Try to answer the following question. If you are not familiar with design patterns, don’t worry! You can learn about them by asking questions like, “Define design patterns.”

Code for the Vending Machine

Requirements for the Online Blackjack Game