每日总结18

计算题卡

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Scanner;

public class suanshi {
    private static final int MAX_NUMBER = 100;//定义最大的数字
    private static final int MIN_NUMBER = 1;

    public static void main(String[] args) {
        int num = 50; // 要生成的题目数量
        List<String> flashcards = generateFlashcards(num);//用于存储生成的题目，generateFlashcards 方法会生成一定数量的题目，并将它们放入 flashcards 中。

        System.out.println("请回答以下口算题：");
        for (int i = 0; i < flashcards.size(); i++) {
            String flashcard = flashcards.get(i);
            System.out.print((i + 1) + ". " + flashcard + " 答案是：");

            Scanner scanner = new Scanner(System.in);//接收用户的答案
            int userAnswer = scanner.nextInt();

            int correctAnswer = evaluateExpression(flashcard);//调用 evaluateExpression 方法计算出正确答案
            if (userAnswer == correctAnswer) {
                System.out.println("回答正确！");
            } else {
                System.out.println("回答错误！正确答案是：" + correctAnswer);
            }
        }
    }
    private static List<String> generateFlashcards(int num) {
        List<String> flashcards = new ArrayList<>();//在 generateFlashcards 方法中创建一个空的 ArrayList 类型的对象 flashcards 用于存储题目
        Random random = new Random();
        for (int i = 0; i < num; i++) {
            int operand1 = random.nextInt(MAX_NUMBER - MIN_NUMBER + 1) + MIN_NUMBER;
            int operand2 = random.nextInt(MAX_NUMBER - MIN_NUMBER + 1) + MIN_NUMBER;
            int operand3 = random.nextInt(MAX_NUMBER - MIN_NUMBER + 1) + MIN_NUMBER;
            int operator = random.nextInt(2); // 0: +, 1: -, 2: *, 3: /
            int operator1 = random.nextInt(2); // 0: +, 1: -, 2: *, 3: /

            String flashcard = generateFlashcard(operand1, operand2, operand3, operator, operator1);

            if (flashcards.contains(flashcard)) {
                // 避免重复的题目
                i--;
            } else {
                flashcards.add(flashcard);
                System.out.println((i + 1) + ". " + flashcard);
            }
        }

        return flashcards;
    }
    private static String generateFlashcard(int operand1, int operand2, int operand3, int operator, int operator1) {
        String operatorSymbol;
        String operatorSymbol1;

        switch (operator) {
            case 0:
                operatorSymbol = "+";
                break;
            case 1:
                operatorSymbol = "-";
                break;

            default:
                throw new IllegalArgumentException("Invalid operator: " + operator);
        }
        switch (operator1) {
            case 0:
                operatorSymbol1 = "+";
                break;
            case 1:
                operatorSymbol1 = "-";
                break;

            default:
                throw new IllegalArgumentException("Invalid operator: " + operator1);
        }

        return  operand1 + " " + operatorSymbol + " " + operand2 + " " + operatorSymbol1+" "+operand3+ " = ";
    }

    private static int evaluateExpression(String flashcard) {//用于计算答案
        String[] parts = flashcard.split(" ");
        int operand1 = Integer.parseInt(parts[0]);
        int operand2 = Integer.parseInt(parts[2]);
        int operand3 = Integer.parseInt(parts[4]);
        String operatorSymbol = parts[1];
        String operatorSymbol1 = parts[3];
        int result1;
        int result2;

        switch (operatorSymbol) {
            case "+":
                result1 = operand1 + operand2;
                break;
            case "-":
                result1 = operand1 - operand2;
                break;
            default:
                throw new IllegalArgumentException("Invalid operator: " + operatorSymbol);//异常处理机制
        }
        switch (operatorSymbol1) {
            case "+":
                result2 = result1 + operand3;
                break;
            case "-":
                result2 = result1 - operand3;
                break;

            default:
                throw new IllegalArgumentException("Invalid operator: " + operatorSymbol1);
        }
        return result2;
    }
}