刚学JAVA,有点地方不太明白,希望帮忙写来参考下!多谢

刚学JAVA,有点地方不太明白,希望大虾帮忙写来参考下!!!谢谢
有五个学生，每个学生有3门课的成绩，从键盘输入以上数据（包括姓名，三门课成绩），计算出平均成绩，并把学生的信息和计算出的平均分数存放在磁盘文件"stud.txt"中.

[解决办法]

Java code

import java.io.FileOutputStream;import java.util.Scanner;/** * Stud.java * 2007-10-7 上午09:48:34 * TODO *//** * @author ustbsjl *  */public class Stud {    /**     * @param args     */    public static void main(String[] args) throws Exception{        // TODO Auto-generated method stub        String name = null;        double firstScore = 0.0;        double secendScore = 0.0;        double thirdScore = 0.0;        double avg = 0.0;        StringBuffer sb = new StringBuffer("[Stu info]\n");        Scanner sc = new Scanner(System.in);        for (int i = 1; i <= 2; i++) {            System.out.println("please enter stu " + i + " info...");            System.out.print("Name: ");            name = sc.next();            System.out.print("FirstScore: ");            firstScore = sc.nextDouble();            System.out.print("SecendScore: ");            secendScore = sc.nextDouble();            System.out.print("ThirdScore: ");            thirdScore = sc.nextDouble();            avg = (firstScore + secendScore + thirdScore) / 3;            System.out.println("This stu's Avg score is " + avg);            sb.append("Name: " + name + ", FirstScore: " + firstScore                    + ", SecendScore: " + secendScore + ", ThirdScore: "                    + thirdScore + ", Avg: " + avg + "\n");        }        FileOutputStream fout = new FileOutputStream("stud.txt");        fout.write(sb.toString().getBytes());    }}