四则运算 Java 杨辉鹏，郑冠华

时间：2018-09-27 22:53:58 阅读：256 评论：0 收藏：0 [点我收藏+]

标签：提升统计帮助 catch erp scan exp nts 题目

GitHub链接：https://github.com/yanghuipeng/arithmetic

项目相关要求

使用 -n 参数控制生成题目的个数，例如

　　　　 -n 10 将生成10个题目。

使用 -r 参数控制题目中数值（自然数、真分数）的范围，例如

　　　　 -r 10

　　　　将生成10以内（不包括10）的四则运算题目。该参数可以设置为1或其他自然数。该参数必须给定，否则程序报错并给出帮助信息。

生成的题目中计算过程不能产生负数，也就是说算术表达式中如果存在形如e1 ? e2的子表达式，那么e1 ≥ e2。
生成的题目中如果存在形如e1 ÷ e2的子表达式，那么其结果应是真分数。
每道题目中出现的运算符个数不超过3个。
程序一次运行生成的题目不能重复，即任何两道题目不能通过有限次交换+和×左右的算术表达式变换为同一道题目。

　　　　生成的题目存入执行程序的当前目录下的Exercises.txt文件，格式如下：

1. 四则运算题目1
2. 四则运算题目2

　　　　其中真分数在输入输出时采用如下格式，真分数五分之三表示为3/5，真分数二又八分之三表示为2’3/8。

在生成题目的同时，计算出所有题目的答案，并存入执行程序的当前目录下的Answers.txt文件，格式如下：

1.答案1

2.答案2

　　　　特别的，真分数的运算如下例所示：1/6 + 1/8 = 7/24。

程序应能支持一万道题目的生成。
程序支持对给定的题目文件和答案文件，判定答案中的对错并进行数量统计，输入参数如下：

　　　　Myapp.exe -e <exercisefile>.txt -a <answerfile>.txt

　　　　统计结果输出到文件Grade.txt，格式如下：

　　　　　　Correct: 5 (1, 3, 5, 7, 9)

　　　　　　Wrong: 5 (2, 4, 6, 8, 10)

　　　　其中“:”后面的数字5表示对/错的题目的数量，括号内的是对/错题目的编号。为简单起见，假设输入的题目都是按照顺序编号的符合规范的题目。

PSP开发耗时

PSP2.1

PSP2.1	Personal Software Process Stages	预估耗时（分钟）	实际耗时（分钟）
Planning	计划	30	50
· Estimate	· 估计这个任务需要多少时间	30	50
Development	开发	1100	2260
· Analysis	· 需求分析 (包括学习新技术)	80	180
· Design Spec	· 生成设计文档	60	100
· Design Review	· 设计复审 (和同事审核设计文档)	30	40
· Coding Standard	· 代码规范 (为目前的开发制定合适的规范)	30	30
· Design	· 具体设计	100	150
· Coding	· 具体编码	600	1500
· Code Review	· 代码复审	50	60
· Test	· 测试（自我测试，修改代码，提交修改）	150	200
Reporting	报告	80	80
· Test Report	· 测试报告	30	40
· Size Measurement	· 计算工作量	20	20
· Postmortem & Process Improvement Plan	· 事后总结, 并提出过程改进计划	30	20
合计		1210	2390

解题思路：

生成随机操作数
取随机操作符
生成表达式
计算
判重
结果写入文件

设计实现过程

Fraction分数类定义一个分数及分数的基本操作
Expression表达式类定义一个表达式及计算表达式的结果
Function输出功能类输出结果

代码

项目目录：

技术分享图片

主函数：（启动程序）Main.java

package TwoProject;

import java.io.*;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) throws IOException {
        // TODO 自动生成的方法存根
        int titleNum; // 定义题目个数
        int parameterRange; // 定义参数范围
        System.out.println("**** -n [数值]     使用 -n 参数控制生成题目的个数");
        System.out.println("**** -e <exercisefile>.txt -a <answerfile>.txt  对给定的题目文件和答案文件，判定答案中的对错并进行数量统计");
        System.out.print("请输入命令：");
        Scanner s = new Scanner(System.in);
        String m = s.nextLine();
        String str[] = m.split("\\s");
        switch (str[0]) {
        case "-n":
            titleNum = Integer.valueOf(str[1].toString());
            System.out.println("**** -r [数值]     使用 -r 参数控制题目中数值（自然数、真分数）的范围(数值应大于1)");
            System.out.print("请输入命令：");
            Scanner ss = new Scanner(System.in);
            String n = ss.nextLine();
            String strr[] = n.split("\\s");
            if (strr[0].equals("-r")) {
                parameterRange = Integer.valueOf(strr[1].toString());
                Function function = new Function(titleNum, parameterRange);
                function.outputExercises();
                break;
            } else {
                System.out.println("输入的命令有误!");
                break;
            }
        case "-e":
            Function function0 = new Function();
            String gradePath = "Grade.txt";
            function0.outputGrade(str[1], str[3], gradePath);
            break;
        default:
            System.out.println("输入的命令有误!");
            break;
        }
        s.close();

    }

}

分数类 Fraction

package TwoProject;

public class Fraction {

    private int a; // 定义分子
    private int b; // 定义分母

    public Fraction(String string) { // 将数字的字符串形式转换为整数、分数形式
        string = string.trim(); // 清除前后空格
        int c = string.indexOf("‘"); // 求带分数标志“‘”的索引
        int d = string.indexOf("/"); // 求分数标志“/”的索引
        if (c != -1) { // 数字为带分数
            int z = Integer.valueOf(string.substring(0, c));
            b = Integer.valueOf(string.substring(d + 1));
            a = z * b + Integer.valueOf(string.substring(c + 1, d));
        } else if (d != -1) { // 数字为真分数
            b = Integer.valueOf(string.substring(d + 1));
            a = Integer.valueOf(string.substring(0, d));
        } else { // 数字为整数
            a = Integer.valueOf(string);
            b = 1;
        }
        build(a, b);
    }

    public Fraction(int a, int b) {
        build(a, b);
    }

    // 数字形式转换为字符串形式
    public String toString() {
        if (b == 1) {
            return String.valueOf(a);
        } else {
            int i = a / b;
            if (i != 0) {
                return String.format("%d‘%d/%d", i, a - b * i, b);
            } else {
                return String.format("%d/%d", a, b);
            }
        }
    }

    // 给定分子分母构造分数
    private void build(int a, int b) {
        if (b == 0) {
            throw new RuntimeException("分母不能为0");
        }
        int c = comfactor(a, b);
        this.a = a / c;
        this.b = b / c;
    }

    // 求公因子
    private int comfactor(int a, int b) {
        int mod = a % b;
        return mod == 0 ? b : comfactor(b, mod);
    }

    // 加法 a + b
    public Fraction add(Fraction fraction) {
        return new Fraction(this.a * fraction.b + fraction.a * this.b, this.b * fraction.b);
    }

    // 减法 a - b
    public Fraction subtraction(Fraction fraction) {
        return new Fraction(this.a * fraction.b - fraction.a * this.b, this.b * fraction.b);
    }

    // 乘法 a x b
    public Fraction multiplication(Fraction fraction) {
        return new Fraction(this.a * fraction.a, this.b * fraction.b);
    }

    // 除法a/b
    public Fraction division(Fraction fraction) {
        return new Fraction(this.a * fraction.b, b * fraction.a);
    }

    public double getDouble() {
        return a / b;
    }
}

表达式类Expression

package TwoProject;

import java.util.List;
import java.util.ArrayList;
import java.util.concurrent.ThreadLocalRandom;

/**
 * 
 * @author 辉鹏
 * @param parameterRange
 *            参数范围
 * 
 * 
 */
public class Expression {
    int parameterRange;
    char[] symbol = { ‘+‘, ‘-‘, ‘×‘, ‘÷‘ };
    boolean isWrong = false;
    String s;
    ThreadLocalRandom random = ThreadLocalRandom.current();
    public Expression(String string) {
        s=string.trim();
        expreGenerate(s);
    }
    public Expression(int parameterRange) {
        super();
        this.parameterRange = parameterRange;
        int n = random.nextInt(1, 4);
        char[] symchar = new char[n];
        char[] symchar1 = new char[n];
        for (int i = 0; i < n; i++) {
            int j = random.nextInt(0, 4);
            symchar[i] = symbol[j];
        }
        for (int i = 0; i < n; i++) {
            if (symchar[i] == ‘+‘ || symchar[i] == ‘-‘) {
                symchar1[i] = ‘1‘;
            }
            if (symchar[i] == ‘×‘ || symchar[i] == ‘÷‘) {
                symchar1[i] = ‘2‘;
            }
        }
        String string = symchar1.toString().trim();
        if (n == 1) {
            String[] str0 = new String[4];
            str0[0] = createFraction().toString();
            str0[1] = String.valueOf(symchar[0]);
            str0[2] = createFraction().toString();
            str0[3] = "=";
            StringBuffer stringBuffer = new StringBuffer();
            for (int i = 0; i < 4; i++) {
                stringBuffer = stringBuffer.append(str0[i] + " ");
            }
            s = stringBuffer.toString();
        } else if (n == 2) {
            if (string == "12" || string == "22") {
                Object[] str1 = new String[6];
                str1[0] = createFraction().toString();
                str1[1] = String.valueOf(symchar[0]);
                str1[2] = createFraction().toString();
                str1[3] = String.valueOf(symchar[1]);
                str1[4] = createFraction().toString();
                str1[5] = "=";
                StringBuffer stringBuffer = new StringBuffer();
                for (int i = 0; i < 6; i++) {
                    stringBuffer = stringBuffer.append(str1[i] + " ");
                }
                s = stringBuffer.toString();
            } else {
                String[] str2 = new String[8];
                str2[0] = createFraction().toString();
                str2[1] = String.valueOf(symchar[0]);
                str2[2] = "(";
                str2[3] = createFraction().toString();
                str2[4] = String.valueOf(symchar[1]);
                str2[5] = createFraction().toString();
                str2[6] = ")";
                str2[7] = "=";
                StringBuffer stringBuffer = new StringBuffer();
                for (int i = 0; i < 8; i++) {
                    stringBuffer = stringBuffer.append(str2[i] + " ");
                }
                s = stringBuffer.toString();
            }
        } else {
            if (string == "221" || string == "222") {
                String[] str3 = new String[10];
                str3[0] = createFraction().toString();
                str3[1] = String.valueOf(symchar[0]);
                str3[2] = createFraction().toString();
                str3[3] = String.valueOf(symchar[1]);
                str3[4] = "(";
                str3[5] = createFraction().toString();
                str3[6] = String.valueOf(symchar[2]);
                str3[7] = createFraction().toString();
                str3[8] = ")";
                str3[9] = "=";
                StringBuffer stringBuffer = new StringBuffer();
                for (int i = 0; i < 10; i++) {
                    stringBuffer = stringBuffer.append(str3[i] + " ");
                }
                s = stringBuffer.toString().trim();

            } else if (string == "111" || string == "112") {
                Object[] str4 = new String[10];
                str4[0] = createFraction().toString();
                str4[1] = String.valueOf(symchar[0]);
                str4[2] = "(";
                str4[3] = createFraction().toString();
                str4[4] = String.valueOf(symchar[1]);
                str4[5] = createFraction().toString();
                str4[6] = ")";
                str4[7] = String.valueOf(symchar[2]);
                str4[8] = createFraction().toString();
                str4[9] = "=";
                StringBuffer stringBuffer = new StringBuffer();
                for (int i = 0; i < 10; i++) {
                    stringBuffer = stringBuffer.append(str4[i] + " ");
                }
                s = stringBuffer.toString().trim();
            } else if (string == "121" || string == "122") {
                Object[] str5 = new String[10];
                str5[0] = "(";
                str5[1] = createFraction().toString();
                str5[2] = String.valueOf(symchar[0]);
                str5[3] = createFraction().toString();
                str5[4] = ")";
                str5[5] = String.valueOf(symchar[1]);
                str5[6] = createFraction().toString();
                str5[7] = String.valueOf(symchar[2]);
                str5[8] = createFraction().toString();
                str5[9] = "=";
                StringBuffer stringBuffer = new StringBuffer();
                for (int i = 0; i < 10; i++) {
                    stringBuffer = stringBuffer.append(str5[i] + " ");
                }
                s = stringBuffer.toString().trim();
            } else {
                Object[] str6 = new String[8];
                str6[0] = createFraction().toString();
                str6[1] = String.valueOf(symchar[0]);
                str6[2] = createFraction().toString();
                str6[3] = String.valueOf(symchar[1]);
                str6[4] = createFraction().toString();
                str6[5] = String.valueOf(symchar[2]);
                str6[6] = createFraction().toString();
                str6[7] = "=";
                StringBuffer stringBuffer = new StringBuffer();
                for (int i = 0; i < 8; i++) {
                    stringBuffer = stringBuffer.append(str6[i] + " ");
                }
                s = stringBuffer.toString().trim();
            }
        }
        expreGenerate(s);
    }

    // 随机生成一个分数
    Fraction createFraction() {
        return new Fraction(random.nextInt(1, parameterRange), random.nextInt(1, 10));
    }

    // 返回一个表达式
    private String expreGenerate(String s) {
        return s;
    }

    // 表达式计算
    private Fraction calculate(String symbol0, Fraction left0, Fraction right0) {
        String symbol = symbol0;
        Fraction left = left0;
        Fraction right = right0;
        switch (symbol) {
        case "+":
            return left.add(right);
        case "-":
            if (left.getDouble() <= right.getDouble()) {
                isWrong = true;
                return new Fraction(1, 1);
            } else {
                return left.subtraction(right);
            }
        case "×":
            return left.multiplication(right);
        default:
            return left.division(right);
        }
    }

    // 表达式结果计算方法
    public String getResult() {
        String string = s;
        String[] strings = string.split("\\s+");
        List<String> list = new ArrayList<String>();
        for (int i = 0; i < strings.length; i++) {
            list.add(strings[i]);
        }
        if (string.indexOf("(") != -1) {
            for (int i = 0; i < list.size(); i++) {
                if (list.get(i).equals("="))
                    break;
                if (list.get(i).equals("(")) {
                    list.set(i, calculate(list.get(i + 2), new Fraction(list.get(i + 1)), new Fraction(list.get(i + 3)))
                            .toString());
                    for (int j = 0; j < 4; j++) {
                        list.remove(i + 1);
                    }
                }
            }
        }
        if (string.indexOf("×") != -1 || string.indexOf("÷") != -1) {
            for (int i = 0; i < list.size(); i++) {
                if (list.get(i).equals("="))
                    break;
                if (list.get(i).equals("×") || list.get(i).equals("÷")) {
                    list.set(i - 1, calculate(list.get(i), new Fraction(list.get(i - 1)), new Fraction(list.get(i + 1)))
                            .toString());
                    for (int j = 0; j < 2; j++) {
                        list.remove(i);
                    }
                    i--;
                }
            }
        }
        if (string.indexOf("+") != -1 || string.indexOf("-") != -1) {
            for (int i = 0; i < list.size(); i++) {
                if (list.get(i).equals("="))
                    break;
                if (list.get(i).equals("+") || list.get(i).equals("-")) {
                    list.set(i - 1, calculate(list.get(i), new Fraction(list.get(i - 1)), new Fraction(list.get(i + 1)))
                            .toString());
                    for (int j = 0; j < 2; j++) {
                        list.remove(i);
                    }
                    i--;
                }
            }
        }
        return list.get(0);
    }

    public String toString() {
        return s;
    }
}

输出功能类Function

package TwoProject;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Set;

/**
 * @param titleNum
 *            题目个数
 * @param parameterRange
 *            参数范围
 */
public class Function {
    int titleNum;
    int parameterRange;
    Set<String> set = new HashSet<>();

    public Function() {

    }

    public Function(int titleNum, int parameterRange) {
        this.titleNum = titleNum;
        this.parameterRange = parameterRange;
    }

    public void outputExercises() {
        try {
            PrintWriter exercisesWriter = new PrintWriter(new FileWriter("Exercises.txt"));
            PrintWriter answerWriter = new PrintWriter(new FileWriter("Answers.txt"));
            for (int i = 1; i < titleNum + 1;) {
                Expression expression = new Expression(parameterRange);
                String string = expression.getResult();
                if (expression.isWrong == false && !(set.contains(string))) {
                    set.add(string);
                    exercisesWriter.println(i + ". " + expression.toString());
                    answerWriter.println((i + ". " + string));
                    i++;
                }
            }
            exercisesWriter.close();
            answerWriter.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println("已经生成题目和答案");
    }

    /**
     * 输出结果
     * 
     * @param exercisePath
     *            表达式文件路径
     * @param answerPath
     *            结果文件路径
     * @param gradePath
     *            输出结果文件路径
     */
    public void outputGrade(String exercisePath, String answerPath, String gradePath) {

        try {
            BufferedReader exercisesReader = new BufferedReader(new FileReader(exercisePath));
            BufferedReader answerReader = new BufferedReader(new FileReader(answerPath));
            PrintWriter gradeWriter = new PrintWriter(new FileWriter(gradePath));
            String exercises, answer;
            int c = 0, w = 0;
            StringBuilder correct = new StringBuilder("Correct: %d (");
            StringBuilder wrong = new StringBuilder("Wrong: %d (");
            while ((exercises = exercisesReader.readLine()) != null && (answer = answerReader.readLine()) != null) {
                int exercisesPoint = exercises.indexOf(".");
                int answerPoint = answer.indexOf(".");
                if (exercisesPoint != -1 && answerPoint != -1) {
                    int i = Integer.valueOf(exercises.substring(0, exercisesPoint).trim());
                    Expression expression = new Expression(exercises.substring(exercisesPoint + 1));
                    Fraction ans = new Fraction(answer.substring(answerPoint + 1));
                    if (expression.getResult().equals(ans.toString())) {
                        c++;
                        correct.append(" " + i);
                        if (c % 30 == 0) {
                            correct.append("\r\n");
                        }
                    } else {
                        w++;
                        wrong.append(" " + i);
                        if (w % 30 == 0) {
                            wrong.append("-r\n");
                        }
                    }
                }
            }
            gradeWriter.println(String.format(correct.append(" )").toString(), c));
            gradeWriter.println(String.format(wrong.append(" )").toString(), w));
            gradeWriter.flush();
            exercisesReader.close();
            answerReader.close();
            gradeWriter.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println("已经比较完成，并生成输出文件");
    }
}