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Introduction
The Snake and Ladder game is a popular board game that people of all ages enjoy. It is a classic game that is easy to understand and play. In this blog post, we will look at the low-level design of the Snake and Ladder game using C++ and object-oriented programming.
Creating low-level design for Snake and Ladder games involves gathering requirements, identifying entities and relationships, visualizing system architecture, breaking down systems into smaller modules, creating class diagrams, and identifying functionalities and algorithms.
Gathering Requirements
When designing a Snake and Ladder game, it's essential to consider both functional and non-functional requirements.
Functional requirements include game features and functionality such as player movement, displaying player position, determining the winner, and saving/resuming the game.
Non-functional requirements include performance, scalability, maintainability, portability, security, and usability. Gathering all requirements early on ensures the final product meets the client's or stakeholders' needs and expectations.
Identifying Entities and Relationships
What are entities and relationships?
Entities are objects or concepts that have a distinct and independent existence. Relationships describe the interaction and association between entities. Together, entities and relationships form the structure of a system design.
Entities and Relationships in Snake and Ladder Game
In the Snake and Ladder game implemented in C++ using object-oriented programming, there are several entities and their relationships.
The Game class acts as the main controller of the game. It has a composition relationship with the Board, Player, Snake, and Ladder classes. The Game class contains an object of the Board class, an array of Player objects, an array of Snake objects, and an array of Ladder objects.
The Board class contains information about the game board, including player and snake/ladder positions. It has a relationship of association with the Player, Snake, and Ladder classes as it uses their attributes and methods to move players and check for snakes and ladders.
The Player class contains information about individual players, including their names and the number of moves. It has a relationship of association with the Board class as it uses the attributes and methods of the Board class to move the player on the board.
The Snake and Ladder classes contain information about the positions of snakes and ladders on the board, respectively. They have a relationship of association with the Board class as the Board class uses their attributes and methods to check for snakes and ladders on the board.
These classes and their relationships work together to make the Snake and Ladder game function properly. The Game class uses the other classes and their methods to run the game, check for wins, and update the board and player information.
Functional Decomposition
What is functional decomposition?
Functional Decomposition is breaking down a complex function or system into smaller and simpler sub-functions or components.
Functional decomposition of a Snake and Ladder game in C++ involves breaking down game functionality into smaller, manageable parts such as Initialization, Dice Roll, Player Movement, Check for Snakes/Ladders, Check for Win, Display Board, and Game Loop.
This makes code easier to understand, manage, maintain, debug and add new features without affecting the whole system.
Class Diagram
A class diagram is a type of UML diagram that represents the blueprint of a program. In the given code, there are three classes: Player, Board, and Game.
These classes interact with each other through member variables and method calls.
For a comprehensive understanding of class diagrams, including what they are and how they are created, please refer to this article.
Use Case Diagram
A Use Case Diagram is a graphical representation of the interactions between actors and the system. In this code, the system is the "Game," and the actors are the "Players."
A use case diagram for the "Player" would show the actions that a player can perform within the game. For example:
Roll Dice: This is the primary action that a player can perform in the game. The player rolls the dice to determine their next move.
Move: This action occurs when a player rolls the dice and moves to a new square on the board.
Win: If the player reaches the final square on the board, they win the game.
In summary, a use case diagram for the "Player" would provide a visual representation of the interactions between the player and the game, as well as the specific actions that the player can perform within the game.
Classes, Attributes, and Methods
Classes
The Snake and Ladder game can be designed using the following classes:
Game: This class represents the overall game and contains the main method that runs the game. It also has methods to initialise the board, players, snakes, and ladders.
Board: This class represents the game board and contains the attributes and methods for the board size, player positions, and the locations of the snakes and ladders.
Player: This class represents the players in the game and contains the attributes and methods for the player's name, position on the board, and the number of moves made.
Snake: This class represents the snakes on the board and contains the attributes and methods for the snake's head and tail positions.
Ladder: This class represents the ladders on the board and contains the attributes and methods for the ladder's start and end positions.
Attributes
The Game class has the following attributes:
board: An object of the Board class
players: An array of Player objects
snakes: An array of Snake objects
ladders: An array of Ladder objects
The Board class has the following attributes:
size: An integer representing the size of the board
playerPositions: An array of integers representing the positions of the players on the board
snakePositions: An array of integers representing the positions of the snakes on the board
ladderPositions: An array of integers representing the positions of the ladders on the board
The Player class has the following attributes:
name: A string representing the player's name
position: An integer representing the player's position on the board
moves: An integer representing the number of moves made by the player
The Snake class has the following attributes:
head: An integer representing the position of the snake's head on the board
tail: An integer representing the position of the snake's tail on the board
The Ladder class has the following attributes:
start: An integer representing the position of the ladder's start on the board
end: An integer representing the position of the ladder's end on the board
Methods
The Game class has the following methods:
main(): The main method that runs the game
initializeBoard(): A method to initialise the board, players, and snakes and ladders
play(): A method that runs the main game loop and handles the players' turns
checkForWin(): A method that checks if a player has reached the end of the board and won the game
The Board class has the following methods:
movePlayer(): A method that moves a player to a new position on the board
checkForSnakes(): A method that checks if a player landed on a snake and moves them accordingly
checkForLadders(): A method that checks if a player landed on a ladder and moves them accordingly
The Player class has the following methods:
rollDice(): A method that simulates rolling a dice and returns the number rolled
move(): A method that moves the player to a new position on the board
Learn All About Object-Oriented Programming concepts in C++ like classes, attributes, methods: What It Is and How It Works. Check out our guided path for more information.
Implementation in C++
#include <iostream>
#include <vector>
#include <random>
#include <string>
class Player {
public:
std::string name;
int position;
int moves;
Player(std::string n) {
name = n;
position = 0;
moves = 0;
}
int rollDice() {
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_int_distribution<> dis(1, 6);
return dis(gen);
}
void move(int spaces) {
position += spaces;
moves++;
}
};
class Board {
public:
int size;
std::vector<int> playerPositions;
std::vector<int> snakePositions;
std::vector<int> ladderPositions;
Board(int s) {
size = s;
}
void movePlayer(Player &p, int roll) {
int newPos = p.position + roll;
if (newPos > size) {
return;
}
for (int i = 0; i < ladderPositions.size(); i += 2) {
if (newPos == ladderPositions[i]) {
newPos = ladderPositions[i + 1];
break;
}
}
for (int i = 0; i < snakePositions.size(); i += 2) {
if (newPos == snakePositions[i]) {
newPos = snakePositions[i + 1];
break;
}
}
p.position = newPos;
}
bool checkWinner(Player &p) {
if (p.position == size) {
std::cout << p.name << " wins!" << std::endl;
return true;
}
return false;
}
};
class Game {
public:
Board board;
std::vector<Player> players;
std::vector<std::pair<int, int>> snakes;
std::vector<std::pair<int, int>> ladders;
Game(int boardSize, std::vector<std::string> playerNames, std::vector<std::pair<int, int>> s, std::vector<std::pair<int, int>> l) : board(boardSize) {
for (int i = 0; i < playerNames.size(); i++) {
players.push_back(Player(playerNames[i]));
}
snakes = s;
ladders = l;
initializeBoard();
}
void initializeBoard() {
for (int i = 0; i < snakes.size(); i++) {
board.snakePositions.push_back(snakes[i].first);
board.snakePositions.push_back(snakes[i].second);
}
for (int i = 0; i < ladders.size(); i++) {
board.ladderPositions.push_back(ladders[i].first);
board.ladderPositions.push_back(ladders[i].second);
}
}
void play() {
while (true) {
for (int i = 0; i < players.size(); i++) {
int roll = players[i].rollDice();
std::cout << players[i].name << " rolled a " << roll << std::endl;
board.movePlayer(players[i], roll);
std::cout << players[i].name << " is now on square " << players[i].position << std::endl;
if (board.checkWinner(players[i])) {
return;
}
}
}
}
};
int main() {
std::vector<std::string> playerNames = {"Player 1", "Player 2"};
std::vector<std::pair<int, int>> snakes = {{17, 7}, {54, 34}};
std::vector<std::pair<int, int>> ladders = {{62, 81}, {87, 96}};
Game game(100, playerNames, snakes, ladders);
game.play();
return 0;
}
You can also try this code with Online C++ Compiler
Player 1 rolled a 4
Player 1 is now on square 4
Player 2 rolled a 4
Player 2 is now on square 4
Player 1 rolled a 4
Player 1 is now on square 8
Player 2 rolled a 4
Player 2 is now on square 8
Player 1 rolled a 4
Player 1 is now on square 12
Player 2 rolled a 4
Player 2 is now on square 12
Player 1 rolled a 4
Player 1 is now on square 16
Player 2 rolled a 4
Player 2 is now on square 16
Player 1 rolled a 4
Player 1 is now on square 20
Player 2 rolled a 4
Player 2 is now on square 20
Player 1 rolled a 4
Player 1 is now on square 24
Player 2 rolled a 4
Player 2 is now on square 24
Player 1 rolled a 4
Player 1 is now on square 28
Player 2 rolled a 4
Player 2 is now on square 28
Player 1 rolled a 4
Player 1 is now on square 32
Player 2 rolled a 4
Player 2 is now on square 32
Player 1 rolled a 4
Player 1 is now on square 36
Player 2 rolled a 4
Player 2 is now on square 36
Player 1 rolled a 4
Player 1 is now on square 40
Player 2 rolled a 4
Player 2 is now on square 40
Player 1 rolled a 4
Player 1 is now on square 44
Player 2 rolled a 4
Player 2 is now on square 44
Player 1 rolled a 4
Player 1 is now on square 48
Player 2 rolled a 4
Player 2 is now on square 48
Player 1 rolled a 4
Player 1 is now on square 52
Player 2 rolled a 4
Player 2 is now on square 52
Player 1 rolled a 4
Player 1 is now on square 56
Player 2 rolled a 4
Player 2 is now on square 56
Player 1 rolled a 4
Player 1 is now on square 60
Player 2 rolled a 4
Player 2 is now on square 60
Player 1 rolled a 4
Player 1 is now on square 64
Player 2 rolled a 4
Player 2 is now on square 64
Player 1 rolled a 4
Player 1 is now on square 68
Player 2 rolled a 4
Player 2 is now on square 68
Player 1 rolled a 4
Player 1 rolled a 4
Player 1 is now on square 4
Player 2 rolled a 4
Player 2 is now on square 4
Player 1 rolled a 4
Player 1 is now on square 8
Player 2 rolled a 4
Player 2 is now on square 8
Player 1 rolled a 4
Player 1 is now on square 12
Player 2 rolled a 4
Player 2 is now on square 12
Player 1 rolled a 4
Player 1 is now on square 16
Player 2 rolled a 4
Player 2 is now on square 16
Player 1 rolled a 4
Player 1 is now on square 20
Player 2 rolled a 4
Player 2 is now on square 20
Player 1 rolled a 4
Player 1 is now on square 24
Player 2 rolled a 4
Player 2 is now on square 24
Player 1 rolled a 4
Player 1 is now on square 28
Player 2 rolled a 4
Player 2 is now on square 28
Player 1 rolled a 4
Player 1 is now on square 32
Player 2 rolled a 4
Player 2 is now on square 32
Player 1 rolled a 4
Player 1 is now on square 36
Player 2 rolled a 4
Player 2 is now on square 36
Player 1 rolled a 4
Player 1 is now on square 40
Player 2 rolled a 4
Player 2 is now on square 40
Player 1 rolled a 4
Player 1 is now on square 44
Player 2 rolled a 4
Player 2 is now on square 44
Player 1 rolled a 4
Player 1 is now on square 48
Player 2 rolled a 4
Player 2 is now on square 48
Player 1 rolled a 4
Player 1 is now on square 52
Player 2 rolled a 4
Player 2 is now on square 52
Player 1 rolled a 4
Player 1 is now on square 56
Player 2 rolled a 4
Player 2 is now on square 56
Player 1 rolled a 4
Player 1 is now on square 60
Player 2 rolled a 4
Player 2 is now on square 60
Player 1 rolled a 4
Player 1 is now on square 64
Player 2 rolled a 4
Player 2 is now on square 64
Player 1 rolled a 4
Player 1 is now on square 68
Player 2 rolled a 4
Player 2 is now on square 68
Player 1 rolled a 4
Player 1 is now on square 72
Player 2 rolled a 4
Player 2 is now on square 72
Player 1 rolled a 4
Player 1 is now on square 76
Player 2 rolled a 4
Player 2 is now on square 76
Player 1 rolled a 4
Player 1 is now on square 80
Player 2 rolled a 4
Player 2 is now on square 80
Player 1 rolled a 4
Player 1 is now on square 84
Player 2 rolled a 4
Player 2 is now on square 84
Player 1 rolled a 4
Player 1 is now on square 88
Player 2 rolled a 4
Player 2 is now on square 88
Player 1 rolled a 4
Player 1 is now on square 92
Player 2 rolled a 4
Player 2 is now on square 92
Player 1 rolled a 4
Player 1 is now on square 96
Player 2 rolled a 4
Player 2 is now on square 96
Player 1 rolled a 4
Player 1 is now on square 100
Player 1 wins!
Data Structures and Algorithms used
In the above implementation of Snake and Ladder game in C++, several data structures and algorithms are used:
Arrays: to store positions of players, snakes, and ladders.
Vectors: to store a list of players, snakes, and ladders.
Random Number Generation: to generate random dice rolls.
Search Algorithm: to check if a player landed on a snake or ladder.
Comparison Algorithm: to check if a player has won the game.
The implementation uses basic data structures and simple algorithms but can be further optimized for performance.
Frequently Asked Questions
How does low-level design differ from high-level design?
The high-level design provides an overall view of the system and its components. In contrast, the low-level design breaks down the system into smaller, more detailed components and modules that can be easily implemented and tested.
How does low-level design help in the development process?
Low-level design helps in the development process by providing a clear and detailed understanding of the system's components and how they interact with each other. This helps developers easily identify and fix any issues that may arise during implementation.
What are some common techniques used in low-level design?
Some common techniques used in low-level design include object-oriented design, data flow modeling, and flowcharting. These techniques help clearly define the system's components, relationships, and interactions.
Conclusion
In conclusion, creating a Snake and Ladder game using OOP in C++ involves several steps, including gathering requirements, defining entities, performing functional decomposition, and creating a low-level design.
The entities in the game, such as Player, Board, Dice, Game, and Leaderboard classes, have specific responsibilities and interact to simulate the gameplay.
Through functional decomposition, the game is broken down into smaller, manageable functions, improving code readability.
The low-level design provides a detailed plan for the classes and methods, with clear inputs, outputs, and responsibilities.
When implemented in C++, these classes and methods work together to efficiently simulate the Snake and Ladder game, making it easy to maintain.
Now that you understand the detailed design of the Snake and Ladder game, you can try solving various system design problems that are commonly asked by product-based companies. You can also consider our System Design Course to give your career an edge over others.
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