Design Snake and Ladder game
Design a Snake and Ladder game that allows multiple players to take turns rolling a dice and move across a board with snakes and ladders using object-oriented design.
Snake and Ladder is a classic turn-based board game played by two or more players on a grid, typically numbered from 1 to 100. Each player starts at cell 1 and takes turns rolling a dice to determine how many steps to move forward.
The game includes:
- Ladders, which boost progress by instantly moving the player up to a higher cell
- Snakes, which hinder progress by sliding the player down to a lower cell
The first player to land exactly on the final cell (e.g., cell 100) is declared the winner.
In this chapter, we will explore the low-level design of a snake and ladder game in detail.
Lets start by clarifying the requirements:
1. Clarifying Requirements
Before starting the design, it's important to ask thoughtful questions to uncover hidden assumptions and better define the scope of the system.
Here is an example of how a conversation between the candidate and the interviewer might unfold:
Candidate: Should the game support a standard 10x10 board with 100 cells, or should the board size be configurable?
Interviewer: For this version, let’s stick with the standard 10x10 board.
Candidate: Should the number and positions of snakes and ladders be fixed, or should they be configurable?
Interviewer: They should be configurable. The board should allow us to define the number and positions of snakes and ladders at initialization.
Candidate: How many players should the game support? Should it be limited to two, or should we support multiple players?
Interviewer: The game should support multiple players—at least two, but potentially more. Player turns should rotate in order.
Candidate: How should dice rolls be handled? Should we simulate a dice roll in the code or take it as input?
Interviewer: Let’s simulate dice rolls using random number generation from 1 to 6. No need for user input for the roll itself.
Candidate: What should happen if a player rolls a 6? Should they get another turn?
Interviewer: Yes, if a player rolls a 6, they get an extra turn immediately.
Candidate: Should a player roll exact number to land on cell 100, or can they overshoot and still win?
Interviewer: A player must land exactly on 100 to win. If the roll takes them beyond 100, their turn is skipped.
Candidate: Can multiple players occupy the same square at the same time?
Interviewer: Yes, more than one player can land on the same square. There's no interaction or conflict when this happens—no "bumping" or penalties.
After gathering the details, we can summarize the key system requirements.
1.1 Functional Requirements
- The game is played on a standard 10x10 board with 100 numbered cells
- Support configuration of snakes and ladders with flexible start and end positions
- Snakes send the player back to a lower-numbered square; ladders move the player forward
- Allow multiple players (minimum two), with turn rotation in round-robin order
- Simulate dice rolls with random values between 1 and 6. A player gets an extra turn if they roll a 6
- A player must roll the exact number to land on cell 100 and win the game
- Multiple players can occupy the same cell without interaction
1.2 Non-Functional Requirements
- Modularity: The system should follow object-oriented principles with clean separation between components
- Extensibility: The design should allow future enhancements such as custom board sizes or different types of dice
- Maintainability: The codebase should be clean, readable, and easy to extend
- User Feedback: The system should provide clear console output after each turn, indicating player moves, dice rolls, snake or ladder interactions, and current positions
After the requirements are clear, lets identify the core entities/objects we will have in our system.