[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。

[C++代码]

#include ＜iostream＞

#include ＜fstream＞

#include ＜string＞

using namespace std;

class Student

private:

string sNO; //学号

int credit; //分数

public:

Student(string a,int b) sNO=a; credit=b;

Student ()

int getCredit ();

void out ();

;

(1) ::getCredit ()

return credit;

(2) ::out ()

cout ＜＜ "SNO: " ＜＜ sNO ＜＜ ", Credit=" ＜＜ credit ＜＜ end1;

class SortStudent

public:

void sort(Student *s, int n);

SortStudent ()

;

void SortStudent::sort(Student *s, int n)

for (int i=0; i＜n-1; i++)

for (int j=i+1; J＜n; j++)

if(s[i]. (3) ＜ s[j]. (4) )

Student temp=s[i]; s[i]=s[j]; s[j]=temp;

int main(int argc, char* argv[])

const int number=100; //学生总数

ifstream Students;

Students.open("students.txt");

if(!students.is_open())

throw 0;

Student *testStudent= (5) [number];

int k=0;

string s;

while (getline(students,s,’＼n’)) //每次读取一个学生的学号和成绩

Student student(s.substr(0，s.find(’,’)), atoi(s.substr(s.find

(’,’)+1).c_str()));

testStudent[k++] = student;

students.colse();

(6) ;

ss.sort(testStudent,k);

cout ＜＜"top 30%: "＜＜end1;

for(k=0; k＜number * 0.3; k++)

testStudent[k].out();

delete []testStudent;

return 0;

（6）处应填（）。