[mw_shl_code=java,true]public class Test11 {
        public static void main(String[] args) throws IOException{
                BufferedReader br =new BufferedReader(new FileReader("c.txt"));
                int i =Integer.parseInt(br.readLine());
                if(i>0){
                System.out.println("还有"+i--+"次机会");
                }else System.out.println("机会用完了");
                BufferedWriter bw = new BufferedWriter(new FileWriter("c.txt"));
                bw.write(String.valueOf(i));
                br.close();
                bw.close();[/mw_shl_code]
有的时候运行会跳到-1去，是为什么啊？

[mw_shl_code=java,true]public class Test11 {
        public static void main(String[] args) throws IOException{
                BufferedReader br =new BufferedReader(new FileReader("c.txt"));
                int i =Integer.parseInt(br.readLine());
                if(i>0){
                System.out.println("还有"+i--+"次机会");
                }else System.out.println("机会用完了");
                BufferedWriter bw = new BufferedWriter(new FileWriter("c.txt"));
                bw.write(String.valueOf(i));
                br.close();
                bw.close();[/mw_shl_code]
有的时候运行会跳到-1去，是为什么啊？