#include <iostream>
#include <cstdlib>
#include <ctime>
#include <string>
#include <cmath>
#include<fstream>

using namespace std;

// 生成随机整数
int RandomNumber(int min, int max) {
    return rand() % (max - min + 1) + min;
}

// 生成随机运算符
char RandomOperator() {
    char operators[] = { '+', '-', '*', '/' };
    return operators[rand() % 4];
}

//定义运算符优先级
int precedence(char op) {
    if (op == '+' || op == '-')
        return 1;
    if (op == '*' || op == '/')
        return 2;
    return 0;
}

// 执行四则运算
double performOperation(double num1, char op, double num2) {
    switch (op) {
    case '+':
        return num1 + num2;
    case '-':
        return num1 - num2;
    case '*':
        return num1 * num2;
    case '/':
        return num1 / num2;
    default:
        return 0.0;
    }
}


int main() {
    srand(time(0)); // 设置随机种子
    ofstream outfile("错题本.txt");
    const int numQuestions = 3; // 生成题目数量
    int correctCount = 0; // 记录答对数量
    cout << "加减乘除的四则运算";
    cout << "(所有结果均保留两位小数!)" << endl;
    // 生成并输出题目
    for (int i = 0; i < numQuestions; ++i) {
        int num1 = RandomNumber(1, 100);
        int num2 = RandomNumber(1, 100);
        int num3 = RandomNumber(1, 100);
        char op1 = RandomOperator();
        char op2 = RandomOperator();

        // 将运算符和数字转换为字符串
        string question = to_string(num1) + " " + op1 + " " + to_string(num2) + " " + op2 + " " + to_string(num3);

        // 计算答案
        double intermediateResult;
        double answer;
        if ((op1 == '/' && num2 == 0) || (op2 == '/' && num3 == 0)) {
            i--;
            continue; // 避免除零错误
        }
        else {
            if (precedence(op2) > precedence(op1)) {
                intermediateResult = performOperation(num2, op2, num3);
                answer = performOperation(num1, op1, intermediateResult);
            }
            else {
                intermediateResult = performOperation(num1, op1, num2);
                answer = performOperation(intermediateResult, op2, num3);
            }
        }
        if (answer < 0 || answer>1000)
        {
            i--;
            continue;
        }
        double reanswer = round(answer * 100) / 100;
        // 输出题目并要求用户输入答案
        cout << "--------------------------------------" << endl;
        cout << "第" << (i + 1) << "题" << ": " << question << " =  ";
        double userAnswer;
        cin >> userAnswer;

        // 判断答案是否正确
        if (userAnswer == reanswer) {
            cout << "回答正确!" << endl;
            correctCount++;
        }
        else {
            cout << "回答错误!" << endl;
            cout<<"正确答案为: " << reanswer << endl;
            outfile << "第" << (i + 1) << "题" << ": " << question << " =  " << endl << "错误答案：" << userAnswer << "   " << "正确答案：" << reanswer << endl;

        }
    }
    outfile.close();
    // 输出总体成绩
    cout << "-------------------------------" << endl;
    cout << "回答正确题目占比: " << correctCount << "/" << numQuestions << endl;
    cout << "注：错题已保留在“错题本.txt”中" << endl;
    cout << "-------------------------------";

    return 0;
}