第17周

#include <iostream>   #include <string>   #include <fstream>      using namespace std;  class Student  {  private:      string name;      float C;      float math;      float english;      float addition;      float average;  public:      Student();      Student(string na, float c,float m, float e, float add, float a);      friend void readfile(Student s[]);      friend void writefile(Student s[]);      friend void showfile(Student s[]);  };    Student::Student()  {      name = " ";      C = 0;      math = 0;      english = 0;      addition = 0;      average = 0;  }  Student::Student(string na, float c,float m, float e, float add, float a)  {      name = na;      C = c;      math = m;      english = e;      addition = add;      average = a;  }  void readfile(Student s[])  {      ifstream file("score.dat", ios::in);      if(! file)      {          cerr << "open error!" << endl;          exit(1);      }      for(int i = 0; i < 100; i++)      {  file >> s[i].name >> s[i].C >> s[i].math >> s[i].english;  s[i].addition = s[i].C + s[i].math + s[i].english;  s[i].average = s[i].addition / 3;      }      file.close();  }    void writefile(Student s[])  {      ofstream file("binary_score.dat", ios::out|ios::binary);      if(! file)      {          cerr << "open error!" << endl;          exit(1);      }      file << "姓名" << '\t' << "C++" << '\t' << "高数"<< '\t' << "英语" << '\t' << "总成绩" << '\t' << "平均成绩" << endl;      for(int i = 0; i < 100; i++)      {  file << s[i].name << '\t' << s[i].C << '\t' << s[i].math << '\t' << s[i].english << '\t' << s[i].addition << '\t' << s[i].average << endl;      }      file << "郭广建" << '\t' << "100" << '\t' << "100" << '\t' << "100" << '\t' << "300" << '\t' << "100" << endl;      file.close();  }    void showfile(Student s[])  {      cout << "姓名" << '\t' << "C++" << '\t' << "高数" << '\t' << "英语" << '\t' << "总成绩" << '\t' << "平均成绩" << endl;      for(int i = 0; i < 100; i++)      {  cout << s[i].name << '\t' << s[i].C << '\t' << s[i].math << '\t' << s[i].english << '\t' << s[i].addition << '\t' << s[i].average << endl;      }      cout << "郭广建" << '\t' << "100" << '\t' << "100" << '\t' << "100" << '\t' << "300" << '\t' << "100" << endl;        }    int main()  {      Student st[100];      readfile(st);      writefile(st);      showfile(st);      system("PAUSE");      return 0;  }