实验与思考作业2

 

import java.util.ArrayList;
import java.util.List;

public class AnswerCalculator {
// 计算题目的答案
public List<Integer> calculateAnswers(List<String> questions) {
List<Integer> answers = new ArrayList<>();
for (String question : questions) {
String[] parts = question.split(" ");
int operand1 = Integer.parseInt(parts[0]);
int operand2 = Integer.parseInt(parts[2]);
String operator = parts[1];
int answer = 0;
switch (operator) {
case "+":
answer = operand1 + operand2;
break;
case "-":
if (operand1 < operand2) {
return null; // 减法不允许出现负数，返回null表示无法计算答案
}
answer = operand1 - operand2;
break;
case "*":
answer = operand1 * operand2;
break;
case "/":
if (operand2 != 0 && operand1 % operand2 == 0) {
answer = operand1 / operand2;
}
else {
return null; // 除法无法整除，返回null表示无法计算答案
}
break;
}
answers.add(answer);
}
return answers;
}
}
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.HashSet;
import java.util.Set;
public class QuestionGenerator {
// 题目不重复的生成和判断
public List<String> generateQuestions(int totalQuestions) {
List<String> questions = new ArrayList<>();
Set<String> questionSet = new HashSet<>(); // 使用HashSet来存储已生成的题目
Random random = new Random();
while (questions.size() < totalQuestions) {
int operand1 = random.nextInt(100)+1;
int operand2 = random.nextInt(100)+1;
String operator = getRandomOperator();
String question = operand1 + " " + operator + " " + operand2;
if (!questions.contains(question) && isValidQuestion(question)) {
questions.add(question);
questionSet.add(question); // 将新生成的题目添加到Set中
}
}
return questions;
}
// 随机生成运算符
private String getRandomOperator() {
String[] operators = {"+", "-", "*", "/"};
Random random = new Random();
int index = random.nextInt(operators.length);
return operators[index];
}
private boolean isValidQuestion(String question) {
String[] parts = question.split(" ");
int operand1 = Integer.parseInt(parts[0]);
int operand2 = Integer.parseInt(parts[2]);
String operator = parts[1];
int answer = 0;
switch (operator) {
case "+":
answer = operand1 + operand2;
break;
case "-":
if (operand1 < operand2) {
return false;
}
answer = operand1 - operand2;
break;
case "*":
answer = operand1 * operand2;
break;
case "/":
if (operand2 != 0 && operand1 % operand2 == 0) {
answer = operand1 / operand2;
}
else {
return false; // 除法无法整除，不符合要求
}
break;
}
return answer >= 0 && answer <= 999; // 乘法结果不能超过3位数
}
}
import java.util.List;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
int totalQuestions = 30; // 题目数量
int correctAnswers = 0; // 正确答案数量
QuestionGenerator generator = new QuestionGenerator();
List<String> questions = generator.generateQuestions(totalQuestions); // 生成题目列表
AnswerCalculator calculator = new AnswerCalculator();
List<Integer> answers = calculator.calculateAnswers(questions); // 计算题目的答案
Scanner scanner = new Scanner(System.in);

System.out.print("请输入答题时间（单位：秒）：");
int timeLimit = scanner.nextInt();
long startTime = System.currentTimeMillis();

// 开始答题
for (int i = 0; i < questions.size(); i++) {
String question = questions.get(i);
System.out.println(question);

// 检查时间限制
long currentTime = System.currentTimeMillis();
int elapsedTime = (int) ((currentTime - startTime) / 1000);
if (elapsedTime >= timeLimit) {
System.out.println("时间到！答题结束。");
break;
}

int userAnswer = scanner.nextInt();
int correctAnswer = answers.get(i);
if (userAnswer == correctAnswer) {
System.out.println("回答正确！");
correctAnswers++;
} else {
System.out.println("回答错误！正确答案是：" + correctAnswer);
}
}
scanner.close();

// 统计正确率
double accuracy = (double) correctAnswers / totalQuestions * 100;
System.out.println("答题结束，正确率为：" + accuracy + "%");
}
}