Java中生成随机运算符并确保每次不同的教程

import java.util.Random;
import java.util.Scanner;

public class RandomOperatorGenerator {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Random randN = new Random();

        // Question 1
        int firstNumbereasy1 = randN.nextInt(9) + 2;
        int secondNumbereasy1 = randN.nextInt(firstNumbereasy1 - 1) + 1; // 确保不为0，避免除零

        String operatorSwitch1 = generateRandomOperator(randN); // 调用辅助方法生成运算符
        int correctAnswer1 = calculateResult(firstNumbereasy1, secondNumbereasy1, operatorSwitch1);

        System.out.println("Question 1, what is " + firstNumbereasy1 + operatorSwitch1 + secondNumbereasy1 + " ?");
        int userAnswer1 = scanner.nextInt();
        System.out.println("Your answer: " + userAnswer1 + ", Correct answer: " + correctAnswer1);

        System.out.println("--------------------");

        // Question 2
        int firstNumbereasy2 = randN.nextInt(9) + 2;
        int secondNumbereasy2 = randN.nextInt(firstNumbereasy2 - 1) + 1; // 确保不为0，避免除零

        String operatorSwitch2 = generateRandomOperator(randN); // 再次调用辅助方法生成新的运算符
        int correctAnswer2 = calculateResult(firstNumbereasy2, secondNumbereasy2, operatorSwitch2);

        System.out.println("Question 2, what is " + firstNumbereasy2 + operatorSwitch2 + secondNumbereasy2 + " ?");
        int userAnswer2 = scanner.nextInt();
        System.out.println("Your answer: " + userAnswer2 + ", Correct answer: " + correctAnswer2);

        scanner.close();
    }

    // 辅助方法：生成随机运算符
    private static String generateRandomOperator(Random random) {
        int operatorIndex = random.nextInt(4); // 修正为nextInt(4)以包含除法运算符
        switch (operatorIndex) {
            case 0: return "+";
            case 1: return "-";
            case 2: return "*";
            case 3: return "/";
            default: return "+"; // 理论上不会执行，作为备用
        }
    }

    // 辅助方法：根据运算符计算结果
    private static int calculateResult(int num1, int num2, String operator) {
        switch (operator) {
            case "+": return num1 + num2;
            case "-": return num1 - num2;
            case "*": return num1 * num2;
            case "/":
                if (num2 == 0) {
                    // 避免除零错误，这里可以抛出异常或返回特定值
                    // 在实际应用中，应确保num2不为0或进行更复杂的处理
                    System.err.println("Error: Division by zero attempted. Returning 0.");
                    return 0;
                }
                return num1 / num2;
            default: return 0; // 默认值
        }
    }
}