试用版软件 10次机会！

package com.heima.test;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class Test18 {

    /**试用版软件 10次机会！ * @param args * @throws IOException */
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader("config.txt"));
        String line = br.readLine();
        int num = Integer.parseInt(line);
        if(num > 0){
            System.out.println("您还有"+ (num--) +"次机会！");
            //BufferedWriter bw = new BufferedWriter(new FileWriter("config.txt"));
            FileWriter bw = new FileWriter("config.txt");
            bw.write(num +"");  //**********
            bw.close();
        }else{
            System.out.println("您的试用机会已满！");
        }
        br.close();
    }

}