14th Week * "Item 2-list of students saved with a file"

Tag:class   c++    inherit    

/**copyright (c) 2014, College of Computer and Control engineering, Yantai University *all rights reserved.* file name: d.cpp* Author: Zhang Wanhua * Completion Date: June 3, 2015 * version number: v1.0*//** " Item 2-The list of students saved with a file "* file Score.dat is a number of students whose names and C + + classes, high scores and English grades are saved. * * #include <fstream> #include <iostream> #include <string> #include <cstdlib>using namespace    std;//defines student class Student{public:student () {};    ~student ();    Double Get_total ();    static int get_stu_num ();    Static double Get_total_sum ();  Friend istream& operator>> (IStream &in, Student &s); You can define the input function instead of friend ostream& operator<< (ostream &out, Student &s);    You can define the display function to replace the bool Pass ();p rivate:string name;    Double CPP;    Double math;    Double 中文版;    Double total;  static int stu_num; Number of pupils, handling static members of the class as appropriate static double total_sum; Student total score and};int Student::stu_num = 0;double student::total_sum = 0;    Student::~student () {total_sum-=total; stu_num--;} Double Student::get_total () {return total;} int Student::get_stu_num () {return stu_nUm;} Double Student::get_total_sum () {return total_sum;} istream& operator>> (IStream &in, Student &s) {in>>s.name>>s.cpp>>s.math>>    S.english;    S.total=s.cpp+s.math+s.english;   student::stu_num++;    In the process of reading data, the number of students and total score and student::total_sum+=s.total are recorded with static members. return in;}    Ostream &operator<< (ostream &out, Student &s) {out<<s.name<< "\ t";    out<<s.cpp<< "\ t";    out<<s.math<< "\ t";    out<<s.english<< "\ t";    out<<s.total; return out;} Returns whether all courses have been all over the bool Student::p () {return cpp>=60 && math>=60 && english>=60;}    int main () {Student stud[200],t;//stud[200] is an array of objects that holds the data string sname;    Double Total_avg;    int i=0;  Reads the data in the file into an array of objects Ifstream infile ("Score.txt", ios::in); Open file as input if (!infile)//test successfully opened {cerr<< "open error!"        <<endl;    Exit (1); } while (!infile.eof ()) {infile>>stud[i++];    In the reading data, the number of people and other information is automatically recorded into the static member, see the implementation of operator overloading} infile.close ();        The total score is averaged and output if (Student::get_stu_num () >0) {total_avg = Student::get_total_sum ()/Student::get_stu_num ();        Ofstream outfile ("Pass_score.dat", ios::out); if (!outfile) {cerr<< "Open error!"            <<endl;        Exit (1); } for (i=0; I<student::get_stu_num (); i++) {if (Stud[i].get_total () >total_avg&&stud[            I].pass ()) {outfile<<stud[i]<<endl;        }} outfile.close ();    cout<< "Please see the list in the file Pass_score.dat:" <<endl; } return 0;}

14th Week * "Item 2-list of students saved with a file"