Feature/fixed quiz scoring

[Prag-18]

Description

This PR resolves an issue in the quiz scoring system (scripts/quiz.js) where the user's score could be artificially inflated. Previously, clicking a correct option repeatedly or toggling between options would continuously increment the score, allowing it to exceed the total number of questions in the quiz.

To fix this, I introduced a robust state-tracking mechanism using a userAnswers object to map each question to its selected answer. The score is now dynamically recalculated whenever an answer changes, ensuring score consistency and preventing duplicate increments.

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🛠️ Changes Made

Resolved #16 Quiz Score Double-Counts on Option Re-Select

Added Answer Tracking State

• Introduced a userAnswers state object to store selections in the format:
  { questionIndex: chosenOptionIndex }

Reset State on Quiz Start

• Initialized and cleared userAnswers inside the startQuiz() function to ensure a clean state for every new quiz session.

Dynamic Score Recalculation

• Refactored selectOption() to:

  • Save the selected option in userAnswers
  • Recompute the score based on all recorded answers
  • Prevent score inflation caused by repeated clicks

Visual Answer Persistence

• Updated showQuestion() to:

  • Restore previously selected answers from userAnswers
  • Keep selections visually highlighted when navigating using the Next and Prev buttons

Prevented Redundant Operations

• Added an early-return guard in selectOption() when the user clicks an already selected option.

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🧪 How to Test / Reproduce

1. Start any quiz (e.g., Web Development Quiz).
2. Click the correct option for Question 1 multiple times.

✅ Expected Behavior

• The score increases by exactly 1 on the first click.
• Repeated clicks on the same correct option do not increase the score further.

3. Select an incorrect option after previously selecting the correct option.

✅ Expected Behavior

• The score decreases correctly by 1.

4. Navigate to the next question, make a selection, then return using the Prev button.

✅ Expected Behavior

• The previously selected option remains restored and visually highlighted.

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✅ Result

• Prevents score manipulation
• Ensures accurate score calculation
• Preserves user selections during navigation
• Improves overall quiz reliability and user experience