package sizeyuansuan;import java.io.*;import java.util.*;public class Sizeyuansuan {    public static void main(String[] args)throws IOException    {        FileOutputStream outfile= new FileOutputStream(new File("sizeyuansuan.txt"));        PrintStream printStream= new PrintStream(outfile);        FileInputStream infile= new FileInputStream("sizeyuansuan.txt");        InputStreamReader reader = new InputStreamReader(infile, "UTF-8");         StringBuffer buffer = new StringBuffer();        Scanner in=new Scanner(System.in);        int a=0;        int b=0;        int sum;        int count=0;        double[] num=new double[100];        int i;        for(i=0;i<100;i++)        {            a= (int)(Math.random()*10+1);            b=(int)(Math.random()*10+1);            int number=(int)(Math.random()*30);            if(number%4==0)            {                sum=a+b;                printStream.print(a);                printStream.print("+");                printStream.print(b);                printStream.print("=");                printStream.print(sum);                printStream.append("\r\n");                num[i]=sum;            }            if(number%4==1)            {                sum=a-b;                printStream.print(a);                printStream.print("-");                printStream.print(b);                printStream.print("=");                printStream.print(sum);                printStream.append("\r\n");                num[i]=sum;            }            if(number%4==2)            {                sum=a*b;                printStream.print(a);                printStream.print("*");                printStream.print(b);                printStream.print("=");                printStream.print(sum);                printStream.append("\r\n");              num[i]=sum;            }            if(number%4==3)            {                sum=a/b;                printStream.print(a);                printStream.print("/");                printStream.print(b);                printStream.print("=");                printStream.print(sum);                printStream.append("\r\n");                num[i]=sum;            }        }        printStream.close();        int test;        double Sum;        for(i=0;i<100;i++)        {        while ((test= reader.read()) != '=')        {            System.out.print((char)test);        }        Sum=in.nextDouble();        if(Sum==num[i])        {            System.out.println("ture");            count++;        }        else        {            System.out.println("false");        }        }        System.out.println("ture:"+count+"   false:"+(100-count));        reader.close();    }}

遇到的困难：1.报错thread "main" java.lang.ArithmeticException: 意思为：运算异常，后我改正了随机数的生成，修改了错误。

                      2.不会缓冲流文本输入，后在网络上学习，学会了缓冲流的输入。

                      3.长数组赋初值初始化麻烦，后采用这种方法初始化double[] num=new double[100];

              备注：除法答案对比无法完成，因为除法答案的小数位除不尽时无法判断。

完成时间：  20:00