Editorial Solution

From the task, we understand that we have to:
- Develop a number guessing game.
- Save the score such that the scores are saved across the controller restart
- Display the leaderboard with the current score if it qualifies for the leaderboard.
For developing the number guessing game, we can do the following:
- Select a random number for a particular session, and maintain a guess count.
- Prompt the user to enter his guess via the serial monitor.
- Increase the guess count for each user’s guess.
- If the user’s guess matches the random number selected, save the current guess count in EEPROM and display the leaderboard.
For displaying the leaderboard:
- Fetch the value from the first 10 locations of the EEPROM.
- Sort the value using the bubble sort and display the leaderboard.
- If the current score is in the leaderboard, put the “You” tag before the score.

Code

#include <EEPROM.h>


// EEPROM Structure
const int HISTORY_ADDR = 0;      // Starting address for score history
const int MAX_HISTORY = 10;      // Track last 10 scores
const int MAX_NUMBER = 100;      // Max number to guess
int randomNumber;                // Randomly generated number
int guesses;                     // Number of guesses in the current session


void setup() {
 Serial.begin(9600);
 randomSeed(analogRead(A0));    // Seed for random number generation
 randomNumber = random(1, MAX_NUMBER + 1);
 guesses = 0;


 Serial.println("Welcome to the Number Guessing Game!");
 Serial.println("Guess the number between 1 and 100.");
 Serial.println();
}


void loop() {
 if (Serial.available()) {
   int guess = Serial.parseInt();


   if(guess == 0)
   {
    /*
     * Handling the NL and CR here
     */
     return;
   }
   else if (guess < 1 || guess > MAX_NUMBER) {
     Serial.println("Invalid input. Please guess a number between 1 and 100.");
     return;
   }


   guesses++;
   if (guess < randomNumber) {
     Serial.println("Too Low!");
   } else if (guess > randomNumber) {
     Serial.println("Too High!");
   } else {
     Serial.print("Correct! You guessed it in ");
     Serial.print(guesses);
     Serial.println(" attempts!");


     saveScore(guesses);
     displayLeaderboard(guesses);
     displayHistory();


     Serial.println("Game Over! Resetting...");
     delay(2000);
     resetGame();
   }
 }
}


void saveScore(int score) {
 // Update history log by shifting older scores
 for (int i = (MAX_HISTORY - 1); i > 0; i--) {
   EEPROM.write(HISTORY_ADDR + i, EEPROM.read(HISTORY_ADDR + (i - 1)));
 }
 // Save the latest score
 EEPROM.write(HISTORY_ADDR, score);


 Serial.println("Saving your score...");
}


void displayLeaderboard(int currentScore) {
 Serial.println("\nLeaderboard:");


 // Fetch and sort the scores
 int scores[MAX_HISTORY];
 int validScores = 0;
 for (int i = 0; i < MAX_HISTORY; i++) {
   int score = EEPROM.read(HISTORY_ADDR + i);
   if (score > 0 && score != 255) { // Ignore invalid or uninitialized scores
     scores[validScores++] = score;
   }
 }


 // Sort scores for ranking
 for (int i = 0; i < validScores - 1; i++) {
   for (int j = i + 1; j < validScores; j++) {
     if (scores[j] < scores[i]) { // Bubble Sort Algorithm
       int temp = scores[i];
       scores[i] = scores[j];
       scores[j] = temp;
     }
   }
 }


 // Display sorted leaderboard with "You" tag for the current score
 bool currentScoreTagged = false;
 for (int i = 0; i < validScores; i++) {
   Serial.print(i + 1);
   Serial.print(". ");
   Serial.print(scores[i]);
   Serial.print(" Guesses");
   if (!currentScoreTagged && scores[i] == currentScore) {
     Serial.print(" (You)");
     currentScoreTagged = true;
   }
   Serial.println();
 }


 if (validScores == 0) {
   Serial.println("No scores available.");
 } else if (!currentScoreTagged) {
   Serial.println("\nYour score is not in the top 10.");
 }
}


void displayHistory() {
 Serial.println("\nLast 10 Scores:");
 for (int i = 0; i < MAX_HISTORY; i++) {
   int score = EEPROM.read(HISTORY_ADDR + i);
   if (score > 0 && score != 255) {
     Serial.print(score);
     Serial.print(" Guesses");
   } else {
     Serial.print("-");
   }
   if (i < MAX_HISTORY - 1) Serial.print(", ");
 }
 Serial.println();
}


void resetGame() {
 randomNumber = random(1, MAX_NUMBER + 1);
 guesses = 0;
 Serial.println("New game started! Guess the number between 1 and 100.");
}

Code Explanation

Display Leaderboard - displayLeaderboard(int currentScore)

Retrieve Scores:

Reads scores from EEPROM (HISTORY_ADDR) and stores valid scores (> 0) into the scores array.

Sort Scores:

Sorts the scores in ascending order to rank players based on the fewest guesses.
Implements a simple Bubble Sort algorithm for sorting the scores.

Highlight Current Session:

Displays the sorted scores with ranks.
Mark the current session's score with (You) if it qualifies for the leaderboard.

Edge Case Handling:

If the current session's score is not in the top 10, it notifies the player.

void displayLeaderboard(int currentScore) {
    Serial.println("\nLeaderboard:");

    int scores[MAX_HISTORY];
    int validScores = 0;
    for (int i = 0; i < MAX_HISTORY; i++) {
        int score = EEPROM.read(HISTORY_ADDR + i);
        if (score > 0) {
            scores[validScores++] = score;
        }
    }

    // Sort scores in ascending order
    for (int i = 0; i < validScores - 1; i++) {
        for (int j = i + 1; j < validScores; j++) {
            if (scores[j] < scores[i]) {
                int temp = scores[i];
                scores[i] = scores[j];
                scores[j] = temp;
            }
        }
    }

    // Display leaderboard
    bool currentScoreTagged = false;
    for (int i = 0; i < validScores; i++) {
        Serial.print(i + 1);
        Serial.print(". ");
        Serial.print(scores[i]);
        Serial.print(" Guesses");
        if (!currentScoreTagged && scores[i] == currentScore) {
            Serial.print(" (You)");
            currentScoreTagged = true;
        }
        Serial.println();
    }

    if (!currentScoreTagged) {
        Serial.println("\nYour score is not in the top 10.");
    }
}

Display History - void displayHistory()

Retrieve History:

Reads the last 10 scores stored sequentially in EEPROM (HISTORY_ADDR).

Display Scores

Iterates through the scores and displays each one in the order they were stored.
Adds formatting (e.g., commas) for better readability.

Handling Empty Entries

Ignores empty or invalid scores (default EEPROM values).
Ensures the history log remains clean and relevant.

void displayHistory() {
    Serial.println("\nLast 10 Scores:");
    for (int i = 0; i < MAX_HISTORY; i++) {
        int score = EEPROM.read(HISTORY_ADDR + i);
        if (score > 0) {
            Serial.print(score);
            Serial.print(" Guesses");
            if (i < MAX_HISTORY - 1) Serial.print(", ");
        }
    }
    Serial.println();
}

OUTPUT

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