四则运算

package 一百;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.Scanner;

public class Build {     
    @SuppressWarnings("resource")
    public static void main (String[] args)throws IOException{
        File file = new File("D:/java/eclipse/100道题/Test.txt"); 
        if(!file.getParentFile().exists()){ //如果文件的目录不存在
            file.getParentFile().mkdirs(); //创建目录           
        }
        FileOutputStream fis=new FileOutputStream(file);
        OutputStreamWriter output = new OutputStreamWriter(fis);
        int[] answer=new int[100];
        for (int i = 0; i < 100; i++) {
            int t = 0;
            String strz = "";   
            int x=(int)(Math.random()*100)+1;
            int y=(int)(Math.random()*100)+1;
            int z=(int)(Math.random()*100)+1;
            if( z<=15 ) {
                strz = "+";
                if ((x+y) > 100) {//相加结果小于等于100        
                    x = x / 2;
                    y = y / 2;
                }
                answer[i]=x+y;
            }
            if( z>15 && z<=30 ) {
                strz = "-";
                if( x < y ){//减数大于被减数
                    t = y;
                    y = x;
                    x = t;
                }
                answer[i]=x-y;
            }
            if( z>30 && z<=45) {//两个个位数相乘
                strz = "×";
                x = x % 10;
                y = y % 10;
                answer[i]=x*y;
            }
            if( z>45 ) {
                strz = "÷";
                y = ( y % 10 ) + 1;//除数不能为0
                if( x % y !=0){//余数不为0
                    strz = "-";
                    if( x < y ){//减数大于被减数
                        t = y;
                        y = x;
                        x = t;
                    }
                    answer[i]=x-y;
                }
                else{
                    answer[i]=x/y;
                }
            }
            String strx = String.valueOf( x );
            String stry = String.valueOf( y );      
            String ques = strx + strz + stry + "=";
            output.write(ques+"\r\n");
        }
        output.close();
        File file1=new File("D:/java/eclipse/100道题/Test.txt");
        int i=0;
        int score=0;
        if(file1.exists()){
            try{
                FileReader fileReader = new FileReader(file1);  
                BufferedReader br = new BufferedReader(fileReader);  
                String lineContent = null;  
                while((lineContent = br.readLine())!=null){  
                    System.out.println(lineContent); 
                    Scanner input = new Scanner(System.in);
                    int a=input.nextInt();
                    if(a==answer[i]) {
                        System.out.println("回答正确！");
                        score++;
                    }
                    else
                    {
                        System.out.println("回答错误! 答案是"+answer[i]);
                    }
                    i++;
                }  
                br.close();  
                fileReader.close();  
            }
            catch (FileNotFoundException e1) {  
                System.out.println("no this file");//文件不存在抛异常  
                e1.printStackTrace();  
            }
            catch (IOException e1) {  
                System.out.println("io exception");  
                e1.printStackTrace();  
            } 
        }
        System.out.println("分数为："+score);
    }
}

用了将近四节课，主要是核对答案时出现错误，数组引用不出来。这次测试让我发现许多自己知识的盲点，以后还会更加努力的。