项目2 - 用文件保存的学生名单

/*
*作者：lws
*完成时间：2014/6/5
*问题描述：文件操作
*/
#include <iostream>
#include <string>
#include <fstream>
#include <cstdlib>
#include <iomanip>
using namespace std;
class Student
{
public:
Student(){}
double getCpp()
{
return cpp;
}
double getMath()
{
return math;
}
double getEnglish()
{
return english;
}
double getTotal()
{
return total;
}
int getStu_num()
{
return stu_num;
}
double getTotal_sum()
{
return total_sum;
}
friend istream &operator>>(istream &in,Student &p);
friend ostream &operator<<(ostream &out,Student &p);
private:
string name;
double cpp;
double math;
double english;
double total;
static int stu_num; //学生人数，处理为类的静态成员合适
static double total_sum; //学生总分和
};
istream &operator>>(istream &in,Student &p)
{
in>>p.name>>p.cpp>>p.math>>p.english;
p.total+=p.cpp+p.math+p.english;
p.stu_num++;
p.total_sum+=p.total;
return in;
}
ostream &operator<<(ostream &out,Student &p)
{
out<<"学生姓名"<<"  "<<"c++成绩"<<"  "<<"数学成绩"<<"  "<<"英语成绩"<<endl
<<p.name<<setw(8)<<p.cpp<<setw(8)<<p.math<<setw(8)<<p.english;
return out;
}
int Student::stu_num=0;
double Student::total_sum=0;
int main()
{
Student stud[200],t;//stud[200]为保存数据的对象数组
string sname;
double total_avg;
int i=0;
//从文件score.dat中读入数据，保存到对象数组中
ifstream input("score.dat",ios::in);
if(!input)
{
cerr<<"open erorr!"<<endl;
exit(1);
}
for(i=0;i!=200;i++)
{
input>>stud[i];
}
input.close();
//总分高于平均总分且没挂科的同学的信息保存到文件pass_score.dat中
ofstream output("pass_score.dat",ios::out);
if(!output)
{
cerr<<"open erorr!"<<endl;
exit(1);
}
for(i=0;i!=200;i++)
{
total_avg=stud[i].getTotal_sum()/stud[i].getStu_num();
if(stud[i].getTotal()>total_avg&&stud[i].getCpp()>60&&stud[i].getMath()>60&&stud[i].getEnglish()>60)
{
output<<stud[i]<<endl;
}
}
output.close();
return 0;
}