Build basic quiz app

QuickQuiz/QuickQuiz/Models/Question.swift

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+import Foundation
+
+struct Question: Identifiable, Equatable {
+    struct Option: Identifiable, Equatable {
+        let id: UUID
+        let text: String
+
+        init(id: UUID = UUID(), text: String) {
+            self.id = id
+            self.text = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        }
+    }
+
+    let id: UUID
+    let prompt: String
+    let options: [Option]
+    let correctOptionID: Option.ID
+    let explanation: String?
+
+    init(
+        id: UUID = UUID(),
+        prompt: String,
+        options: [Option],
+        correctOptionID: Option.ID,
+        explanation: String? = nil
+    ) {
+        precondition(!options.isEmpty, "Questions must offer at least one option")
+        precondition(options.contains(where: { $0.id == correctOptionID }), "Correct option must exist in options list")
+
+        self.id = id
+        self.prompt = prompt.trimmingCharacters(in: .whitespacesAndNewlines)
+        self.options = options
+        self.correctOptionID = correctOptionID
+        self.explanation = explanation?.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    init(prompt: String, answers: [String], correctIndex: Int, explanation: String? = nil) {
+        precondition(!answers.isEmpty, "Questions must offer at least one option")
+        precondition(answers.indices.contains(correctIndex), "Correct answer index is out of bounds")
+
+        let builtOptions = answers.map { Option(text: $0) }
+        let correctID = builtOptions[correctIndex].id
+        self.init(
+            prompt: prompt,
+            options: builtOptions,
+            correctOptionID: correctID,
+            explanation: explanation
+        )
+    }
+}

QuickQuiz/QuickQuiz/Models/QuestionBank.swift

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+import Foundation
+
+enum QuestionBank {
+    /// Replace the sample questions below with your own content.
+    static let defaultQuestions: [Question] = [
+        Question(
+            prompt: "When did Apple introduce SwiftUI?",
+            answers: ["2014", "2016", "2019", "2021"],
+            correctIndex: 2,
+            explanation: "SwiftUI debuted during WWDC19."
+        ),
+        Question(
+            prompt: "Which keyword lets SwiftUI views refresh automatically when data changes?",
+            answers: ["@Binding", "@State", "@Published", "@ObservedObject"],
+            correctIndex: 1,
+            explanation: "@State keeps local view state and triggers updates."
+        ),
+        Question(
+            prompt: "What Xcode preview device most closely matches a standard iPhone size?",
+            answers: ["iPhone SE", "iPhone 15 Pro", "Apple Watch Ultra", "iPad mini"],
+            correctIndex: 1,
+            explanation: "The 6.1\" class (e.g. iPhone 15 Pro) is the common default."
+        )
+    ]
+}

QuickQuiz/QuickQuiz/QuickQuizApp.swift

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+import SwiftUI
+
+@main
+struct QuickQuizApp: App {
+    @StateObject private var viewModel = QuizViewModel(questions: QuestionBank.defaultQuestions)
+
+    var body: some Scene {
+        WindowGroup {
+            QuizView(viewModel: viewModel)
+        }
+    }
+}

QuickQuiz/QuickQuiz/ViewModels/QuizViewModel.swift

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+import Foundation
+import SwiftUI
+
+final class QuizViewModel: ObservableObject {
+    @Published private(set) var questions: [Question]
+    @Published private(set) var currentIndex: Int = 0
+    @Published private(set) var score: Int = 0
+    @Published private(set) var isComplete: Bool = false
+    @Published var selectedOptionID: Question.Option.ID? = nil
+    @Published private(set) var hasAnswered: Bool = false
+
+    init(questions: [Question]) {
+        precondition(!questions.isEmpty, "Provide at least one question")
+        self.questions = questions
+    }
+
+    var currentQuestion: Question {
+        questions[currentIndex]
+    }
+
+    var progressText: String {
+        "Question \(currentIndex + 1) of \(questions.count)"
+    }
+
+    var scoreText: String {
+        "Score: \(score) / \(questions.count)"
+    }
+
+    func select(option: Question.Option) {
+        guard !hasAnswered else { return }
+        selectedOptionID = option.id
+        hasAnswered = true
+        if option.id == currentQuestion.correctOptionID {
+            score += 1
+        }
+
+        if currentIndex == questions.count - 1 {
+            isComplete = true
+        }
+    }
+
+    func goToNextQuestion() {
+        guard currentIndex < questions.count - 1 else {
+            isComplete = true
+            return
+        }
+
+        currentIndex += 1
+        selectedOptionID = nil
+        hasAnswered = false
+    }
+
+    func restart(shuffleQuestions: Bool = true) {
+        if shuffleQuestions {
+            questions.shuffle()
+        }
+
+        currentIndex = 0
+        score = 0
+        isComplete = false
+        selectedOptionID = nil
+        hasAnswered = false
+    }
+}

QuickQuiz/QuickQuiz/Views/QuizView.swift

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+import SwiftUI
+
+struct QuizView: View {
+    @ObservedObject var viewModel: QuizViewModel
+
+    var body: some View {
+        NavigationStack {
+            VStack(alignment: .leading, spacing: 24) {
+                header
+                questionCard
+                optionsList
+                explanationSection
+                Spacer()
+                actionButtons
+            }
+            .padding(24)
+            .background(
+                LinearGradient(
+                    colors: [Color(.systemBackground), Color(.secondarySystemBackground)],
+                    startPoint: .top,
+                    endPoint: .bottom
+                )
+                .ignoresSafeArea()
+            )
+            .navigationTitle("Quick Quiz")
+        }
+    }
+
+    private var header: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            Text(viewModel.progressText)
+                .font(.headline)
+                .foregroundStyle(.secondary)
+            ProgressView(value: Double(viewModel.currentIndex + 1), total: Double(viewModel.questions.count))
+            Text(viewModel.scoreText)
+                .font(.subheadline)
+                .bold()
+        }
+    }
+
+    private var questionCard: some View {
+        Text(viewModel.currentQuestion.prompt)
+            .font(.title2.weight(.semibold))
+            .padding()
+            .frame(maxWidth: .infinity, alignment: .leading)
+            .background(RoundedRectangle(cornerRadius: 16).fill(Color(.tertiarySystemBackground)))
+    }
+
+    private var optionsList: some View {
+        VStack(spacing: 12) {
+            ForEach(viewModel.currentQuestion.options) { option in
+                OptionButton(
+                    option: option,
+                    isSelected: option.id == viewModel.selectedOptionID,
+                    isCorrect: option.id == viewModel.currentQuestion.correctOptionID,
+                    hasAnswered: viewModel.hasAnswered
+                ) {
+                    viewModel.select(option: option)
+                }
+                .disabled(viewModel.hasAnswered)
+            }
+        }
+    }
+
+    private var explanationSection: some View {
+        Group {
+            if viewModel.hasAnswered, let explanation = viewModel.currentQuestion.explanation {
+                Text(explanation)
+                    .font(.callout)
+                    .foregroundStyle(.secondary)
+                    .padding(.horizontal)
+            }
+        }
+    }
+
+    private var actionButtons: some View {
+        VStack(spacing: 12) {
+            if viewModel.isComplete {
+                Button(action: { viewModel.restart() }) {
+                    Label("Restart Quiz", systemImage: "arrow.clockwise")
+                        .frame(maxWidth: .infinity)
+                }
+                .buttonStyle(.borderedProminent)
+            } else {
+                Button(action: viewModel.goToNextQuestion) {
+                    Label("Next", systemImage: "chevron.right")
+                        .frame(maxWidth: .infinity)
+                }
+                .buttonStyle(.borderedProminent)
+                .disabled(!viewModel.hasAnswered)
+            }
+
+            Button(action: { viewModel.restart(shuffleQuestions: false) }) {
+                Label("Start Over (same order)", systemImage: "arrow.counterclockwise")
+                    .frame(maxWidth: .infinity)
+            }
+            .buttonStyle(.bordered)
+        }
+    }
+}
+
+private struct OptionButton: View {
+    let option: Question.Option
+    let isSelected: Bool
+    let isCorrect: Bool
+    let hasAnswered: Bool
+    let tapAction: () -> Void
+
+    var body: some View {
+        Button(action: tapAction) {
+            HStack {
+                Text(option.text)
+                    .font(.body.weight(.medium))
+                    .multilineTextAlignment(.leading)
+                Spacer()
+                if hasAnswered {
+                    Image(systemName: isCorrect ? "checkmark.circle.fill" : (isSelected ? "xmark.circle.fill" : "circle"))
+                        .foregroundStyle(iconColor)
+                }
+            }
+            .padding()
+            .frame(maxWidth: .infinity)
+        }
+        .buttonStyle(.plain)
+        .background(RoundedRectangle(cornerRadius: 14).fill(backgroundColor))
+        .overlay(
+            RoundedRectangle(cornerRadius: 14)
+                .stroke(borderColor, lineWidth: 1)
+        )
+    }
+
+    private var backgroundColor: Color {
+        guard hasAnswered else {
+            return Color(.secondarySystemBackground)
+        }
+        if isCorrect {
+            return Color.green.opacity(0.2)
+        }
+        if isSelected {
+            return Color.red.opacity(0.2)
+        }
+        return Color(.secondarySystemBackground)
+    }
+
+    private var borderColor: Color {
+        guard hasAnswered else {
+            return Color.clear
+        }
+        return isCorrect ? .green : (isSelected ? .red : .clear)
+    }
+
+    private var iconColor: Color {
+        isCorrect ? .green : (isSelected ? .red : .secondary)
+    }
+}
+
+#Preview
+struct QuizView_Previews: PreviewProvider {
+    static var previews: some View {
+        QuizView(viewModel: QuizViewModel(questions: QuestionBank.defaultQuestions))
+    }
+}

QuickQuiz/README.md

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+# QuickQuiz
+
+Lightweight SwiftUI multiple-choice quiz that works entirely on-device. There is no login, backend, or analytics—just hard-coded questions you can edit in seconds.
+
+## Project layout
+
+```
+QuickQuiz/
+├─ QuickQuizApp.swift          // Entry point
+├─ Models/
+│  ├─ Question.swift           // Data structures for questions & answers
+│  └─ QuestionBank.swift       // Sample questions to edit later
+├─ ViewModels/
+│  └─ QuizViewModel.swift      // Quiz state machine (progress, scoring)
+└─ Views/
+   └─ QuizView.swift           // UI for asking questions and selecting answers
+```
+
+## How to get it running in < 5 minutes
+
+1. **Create a new SwiftUI app in Xcode** (File → New → Project → iOS App). Name it `QuickQuiz` (or anything you like) and choose "SwiftUI" for the interface.
+2. **Copy the files from this folder into your project**:
+   - Replace the autogenerated `App` file with `QuickQuizApp.swift`.
+   - Add the `Models`, `ViewModels`, and `Views` folders (right-click your Xcode project → "Add Files to ..." → select the folders).
+3. **Build & run** on the simulator or your plugged-in iPhone. Code-signing is already handled by your existing Apple developer setup.
+
+## Editing the question later
+
+Open `QuestionBank.swift` and replace the sample `Question` entries with your real content. Each `Question` takes:
+```swift
+Question(
+    prompt: "What is 2 + 2?",
+    answers: ["3", "4", "5", "6"],
+    correctIndex: 1,
+    explanation: "Because 2 + 2 = 4."
+)
+```
+Add as many questions as you need; the UI automatically updates the progress tracker and score.
+
+## Notes
+
+- Everything is computed on-device, so it works offline.
+- `QuizViewModel` includes a quick `restart()` helper that reshuffles the questions; hook it up to any button if you want different behavior.
+- Feel free to theme the colors or typography—everything lives in `QuizView`.