四则运算1.1版

package Better;

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

public class Main {
    int number1;
    int number2;
    char mark;
    String answer;

    public static void produce(Main[] calation) {
        int convert = 0;
        Random a = new Random();
        char[] ch = { '+', '-', '*', '/' }; // 字符数组
        Random b = new Random();
        for (int i = 0; i < calation.length; i++) {
            calation[i].number1 = a.nextInt(100)+1;
            calation[i].number2 = a.nextInt(100)+1;
            int node = b.nextInt(4);
            calation[i].mark = ch[node];
            switch (calation[i].mark) {
            case '+':
                convert = calation[i].number1 + calation[i].number2;break;
            case '-':
                convert = calation[i].number1 - calation[i].number2;break;
            case '*':
                convert = calation[i].number1 * calation[i].number2;break;
            case '/':
                convert = calation[i].number1 / calation[i].number2;break;
            }
            calation[i].answer = Integer.toString(convert);
        }
    }

    public static void storage(Main[] calation) {
        FileOutputStream fos = null;
        PrintStream ps = null;
        try {
            fos = new FileOutputStream("Test.txt", true);
            ps = new PrintStream(fos);
            for (int i = 0; i < calation.length; i++) {
                ps.print(calation[i].number1);
                ps.print(calation[i].mark);
                ps.print(calation[i].number2);
                ps.println('=');
            }
            fos.close();
            ps.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static String readTxtLine(String txtPath, int lineNo) {

        String line = "";
        String encoding = "GBK";
        try {
            File txtFile = new File(txtPath);
            InputStream in = new FileInputStream(txtFile);
            InputStreamReader read = new InputStreamReader(in, encoding);
            BufferedReader reader = new BufferedReader(read);
            int i = 0;
            while (i < lineNo) {
                line = reader.readLine();
                i++;
            }
            reader.close();
        } catch (Exception e) {
            // TODO: handle exception
        }
        return line;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String txtPath = "D:/java/Better/Test.txt";
        int trueanswer = 0, falseanswer = 0, account = 0;
        int lineNo = 0;
        Main[] a = new Main[100];
        for (int i = 0; i < a.length; i++) {
            a[i]=new Main();
        }
        String result;
        produce(a);
        storage(a);
        for (int i = 0; i < a.length; i++) {
            lineNo = i + 1;
            System.out.println(readTxtLine(txtPath, lineNo));
            result = in.nextLine();
            if (result.equals("*"))
                break;
            else if (result.equals(a[i].answer))
                trueanswer++;
            else
                falseanswer++;
        }
        account = trueanswer + falseanswer;
        System.out.println("您一共做了" + account + "道题");
        System.out.println("答对" + trueanswer + "道题");
        System.out.println("答错" + falseanswer + "道题");
        System.out.println("题目及答案如下");
        for (int i = 0; i <account; i++) {
            System.out.print(a[i].number1);
            System.out.print(a[i].mark);
            System.out.print(a[i].number2);
            System.out.print("=");
            System.out.println(a[i].answer);
        }
    }
}

我把之前的版本分模块后，每个具体的功能写进了方法里，并且把每个方法进行测试，直至单独能够运行，最后拼接成整个大程序。