1
function random_add_quiz() {
2
  let correctAnswers = 0;
3
  let totalQuestions = 10;
4
  for (let i = 0; i < totalQuestions; i++) {
5
    let num1 = Math.floor(Math.random() * 100) + 1;
6
    let num2 = Math.floor(Math.random() * 100) + 1;
7
    let sum = num1 + num2;
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    let userAnswer = window.prompt("What is the sum of " + num1 + " and " + num2 + "?");
9
    if (parseInt(userAnswer, 10) === sum) {
10
      window.alert("Correct! The sum is indeed " + sum + ".");
11
      correctAnswers++;
12
    } else {
13
      window.alert("Incorrect. The sum is: " + sum);
14
    }
15
  }
16
  window.alert("You got " + correctAnswers + " out of " + totalQuestions + " correct!");
17
}

1
function guess_number() {
2
  let randomNum = Math.floor(Math.random() * 20) + 1;
3
  let attempts = 0;
4
  let maxAttempts = 5;
5
  let guess;
6
  for (attempts = 0; attempts < maxAttempts; attempts++) {
7
    guess = parseInt(window.prompt("Guess a number between 1 and 20 (Attempt " + (attempts + 1) + " of " + maxAttempts + "):"), 10);
8
    if (isNaN(guess)) {
9
      window.alert("Please enter a valid number.");
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      attempts--; // Don't count invalid input as an attempt
11
    } else if (guess < randomNum) {
12
      window.alert("Too low! Try again.");
13
    } else if (guess > randomNum) {
14
      window.alert("Too high! Try again.");
15
    } else {
16
      window.alert("Congratulations! You guessed the number!");
17
      return; // Exit the function if guessed correctly
18
    }
19
  }
20
  window.alert("Sorry, you've used all attempts! The number was: " + randomNum);
21
}

1
function fibonacci(n) {
2
  let fibonacciSequence = [0, 1];
3
  for (let i = 2; i < n; i++) {
4
    fibonacciSequence[i] = fibonacciSequence[i - 1] + fibonacciSequence[i - 2];
5
  }
6
  return fibonacciSequence.slice(0, n);
7
}
8

9
function displayFibonacci() {
10
  // let n = parseInt(window.prompt("How many Fibonacci numbers to display?"), 10);
11
  let n = 10;
12
  if (isNaN(n) || n <= 0) {
13
    window.alert("Please enter a valid positive integer.");
14
  } else {
15
    let fibSequence = fibonacci(n);
16
    window.alert("The first " + n + " Fibonacci numbers are:\n" + fibSequence.join(", "));
17
  }
18
}

1
class Car {
2
  constructor(make, model, year) {
3
    this.make = make;
4
    this.brand = make; // brand 是 make 的别名
5
    this.model = model;
6
    this.year = year;
7
  }
8
  displayInfo() {
9
    return `${this.year} ${this.brand} ${this.model}`;
10
  }
11
}
12
function testCar() {
13
  let car1 = new Car("Toyota", "Corolla", 2020);
14
  let car2 = new Car("Honda", "Civic", 2019);
15
  window.alert("Car 1: " + car1.displayInfo() + "\nCar 2: " + car2.displayInfo());
16
}

1
let people = [
2
  {
3
    name: "Alice",
4
    age: 28,
5
    car: new Car("Toyota", "Camry", 2018),
6
    greet: function() { return `Hello, my name is ${this.name}.`; }
7
  },
8
  {
9
    name: "Bob",
10
    age: 35,
11
    car: new Car("Honda", "Accord", 2020),
12
    greet: function() { return `Hello, my name is ${this.name}.`; }
13
  },
14
  {
15
    name: "Charlie",
16
    age: 22,
17
    car: new Car("Ford", "Focus", 2017),
18
    greet: function() { return `Hello, my name is ${this.name}.`; }
19
  },
20
  {
21
    name: "Diana",
22
    age: 31,
23
    car: new Car("Toyota", "Corolla", 2021),
24
    greet: function() { return `Hello, my name is ${this.name}.`; }
25
  },
26
  {
27
    name: "Ethan",
28
    age: 27,
29
    car: new Car("Honda", "Civic", 2019),
30
    greet: function() { return `Hello, my name is ${this.name}.`; }
31
  }
32
];
33

34
// Find all brands and group people by brand
35
function displayPeopleByCarBrand() {
36
  let brandMap = {};
37
  for (let person of people) {
38
    let brand = person.car.brand;
39
    if (!brandMap[brand]) {
40
      brandMap[brand] = [];
41
    }
42
    brandMap[brand].push(person.name);
43
  }
44
  let brands = Object.keys(brandMap).sort();
45
  let result = "People by car brand:\n";
46
  for (let brand of brands) {
47
    result += brand + ": " + brandMap[brand].join(", ") + "\n";
48
  }
49
  window.alert(result);
50
}

1
function calculate() {
2
  let num1 = parseFloat(window.prompt("Enter the first number:"));
3
  let num2 = parseFloat(window.prompt("Enter the second number:"));
4
  let operation = window.prompt("Enter operation: add, sub, mul, or div").toLowerCase();
5

6
  const operations = {
7
    add: (a, b) => a + b,
8
    sub: (a, b) => a - b,
9
    mul: (a, b) => a * b,
10
    div: (a, b) => a / b
11
  };
12

13
  let result = operations[operation]?.(num1, num2);
14

15
  document.body.innerHTML += `<p>Result: ${result !== undefined ? result : "Invalid operation"}</p>`;
16
}