[说明]某数据文件students.txt的内容为100名学生的学号和成绩，下面的程

问题：

[说明]

某数据文件students.txt的内容为100名学生的学号和成绩，下面的程序将文件中的数据全部读入对象数组，按分数从高到低进行排序后，选出排名前30%的学生。

[Java代码]

import Java.io.*;

class Student

private string sNO; //学号

private int credit; //分数

public int getCredit ()

return Credit;

public String toString ()

return"sNO="+this.sNO+", Credit="+this.Credit;

Student(String sNO, int Credit)

(1) =sNO;

(2) =Credit;

public class SortStudent

void sort(Student[] s) //Sort the array s[] in descending order of

Credit

for (int i=0; i ＜ s.length-1; i++)

for (int j=i+1; j ＜ s.length; j++)

if (s[i]. (3) ＜ s[j]. (4) )

Student tmp=s[i];

s[i]=s[j];

s[j]=tmp;

public static void main(String argv[])

Student[] testStudent = new Student[size];

try

BufferedReader in = new BufferedReader(new FileReader

("Students.txt"));

boolean done = false;

int i = 0;

while (!done)

String s = in.readLine(); //每次读取一个学生的学号和成绩

if (s !=null)

String tmp[] = s.split(",");

testStudent[i++] = (5) (tmp[0], Integer.parseInt

(tmp[1]));

else

done = true;

in.close();

(6) =new SortStudent();

ss.sort(testStudent);

System.out.println("top 30%:");

for (int j = 0; j ＜ size * 0.3; j++)

System.out.println(testStudent[j]);

catch (IOException e)

System.out.println("io error!");

catch (NumberFormatException e)

System.out.println("not a number!");

(7) int size = 100; //学生总数

（4）处应填（）。