Java四则运算V3.0

第三版基本完成了

题目：

课堂测试3： 2、可定制（数量/打印方式）：输入大的数量值，测试一下系统是否崩溃，反向查找系统是否优化的余地； 3、定制操作数的个数：4、定制是否有乘除法 5、定制是否有括号（随机加入） 6 、定制数值范围（确定操作数的取值范围）

package demo;
import java.util.Scanner;

public class chuti {

    static String[] question = new String[100];
    static int[] answer = new int[100];

    public static int getRandom(int n, int m) {
        // 产生n->m的随机数
        return (int) (Math.random() * (m - n) + n);
    }

    public static char getCharRandom() {
        // 随机产生四种运算符
        char sign = 0;
        int Sn;
        Sn = getRandom(1, 5);
        switch (Sn) {
        case 1:
            sign = '+';
            break;
        case 2:
            sign = '-';
            break;
        case 3:
            sign = '×';
            break;
        case 4:
            sign = '÷';
            break;
        }
        return sign;
    }

    public static  void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner cin = new Scanner(System.in);
        //File file = new File("E:\\szys.txt");
        int i = 0;
        int huida,score = 0;
         do
         {
             int  x = (int) (Math.random() * (100 - 1 )+ 1);  //产生1-100的随机数
             int  y = (int) (Math.random() * (100 - 1 )+ 1);  //产生1-100的随机数
             char sign = getCharRandom();
             /*
              * 判断乘法的范围*/
             switch(sign)
             {
             case '+':
                 question[i] = x +""+ sign +""+ y + "=";
                 huida = x + y;
                 answer[i] = huida;
                 //System.out.println( "("+ (i+1) +")"+ x + " " + sign + " " + y + "="     );
                 i++;break;
             case '-':
                 if(x < y)                        //判断减数与被减数的大小关系
                 {
                     int temp;
                     temp = x;
                     x = y;
                     y = temp;
                 }
                 question[i] = x +""+ sign +""+ y + "=";
                 huida = x - y;
                 answer[i] = huida;
                 //System.out.println( "("+ (i+1) +")"+ x + " " + sign + " " + y + "="     );
                 i++;break;
             case '×':
             {
                 x = (int) (Math.random() * (10 - 1 )+ 1);//新生成x,y<9的随机数
                 y = (int) (Math.random() * (10 - 1 )+ 1);
                 question[i] = x +""+ sign +""+ y + "=";
                 huida = x * y;
                 answer[i] = huida;
                     //System.out.println( "("+ (i+1) +")"+ x + " " + sign + " " + y + "="     );
                 i++;
             };break;
             case '÷':
                 do                                             //循环生成除法
                 {
                     y = (int) (Math.random() * (10 - 1 )+ 1);
                     x = (int) (Math.random() * (9*y - 1 )+ 1);

                 }
                while(x % y != 0) ;
                question[i] = x +""+ sign+"" + y + "=";
                huida = x / y;
                 answer[i] = huida;
                //System.out.println( "("+ (i+1) +")"+ x + " " + sign + " " + y + "="     );
                i++;break;
                 }
        }
        while(i<10);


    try {
            BufferedWriter br= new BufferedWriter(new FileWriter("szys.txt"));
            for(int k = 0;k<10;k++)
            {
                br.write("("+(k+1)+")"+String.valueOf(question[k])+"*"+String.valueOf(answer[k]));//读取数组进缓冲区
                br.newLine();//写入新的一行，换行
                br.flush();//将缓冲区存入txt
            }
        } catch (IOException e) {
        //文件读写异常
        e.printStackTrace();
    }

    try {
            String line = null;
            BufferedReader re = new BufferedReader(new FileReader("szys.txt"));//新定义
            while((line = re.readLine())!= null)
            {//逐行读取文件
                String [] txt = line.split("\\*");//以*为分界，将.txt分开成问题和答案两块
                System.out.println(txt[0]);//输出题目
                System.out.print("Your answer:");
                String an = cin.next();
                if(txt[1].equals(an))//判断答案与回答
                {
                    System.out.println("回答正确！");
                    score++;
                }
                else
                    System.out.println("回答错误！正确答案：" + txt[1]);
            }
            System.out.println("共答对"+ score + "题，答错" + (10-score) + "题");
    }catch(IOException e)
        {
            e.printStackTrace();
        }

}
}