第十四周项目2-用文件保存的学生名单

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（1）定义学生类，其中包含姓名、C++课、高数和英语成绩及总分数据成员。

//定义学生类
class Student{
public:
    //声明必要的成员函数
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
};

#include <iostream>
#include <cstdlib>
#include <fstream>
using namespace std;
//定义学生类
class Student
{
public:
    Student() {};
    void input();
    void display();
    double get_total()
    {
        return total;
    }
    static int get_stu_num()
    {
        return stu_num;
    }
    static double get_total_sum()
    {
        return total_sum;
    }
    bool pass();
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
    friend istream& operator>>(istream &in, Student &s); 
    friend ostream& operator<<(ostream &out, Student &s);
};
int Student::stu_num=0;
double Student::total_sum=0;
bool Student::pass()
{
    if (cpp>=60 && math>=60 && english>=60)
        return true;
    else
        return false;
}
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++;
    Student::total_sum+=s.total;
    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;
}
int main()
{
    Student stu[200];
    int num=0,i;
    double total_avg;
    ifstream infile("score.dat",ios::in);
    if(!infile)
    {
        cerr<<"error!"<<endl;
        exit(1);
    }
    while (!infile.eof())
    {
        infile>>stu[num++];
    }
    infile.close();
    total_avg = Student::get_total_sum() / Student::get_stu_num();
    ofstream outfile("pass_score.dat",ios::out);
    if(!outfile)
    {
        cerr<<"error!"<<endl;
        exit(1);
    }
    for(i=0; i<Student::get_stu_num(); i++)
    {
        if (stu[i].get_total()>total_avg)
        {
            if (stu[i].pass())
            {
                outfile<<stu[i]<<endl;
            }
        }
    }
}

@ Mayuko

第十四周项目2-用文件保存的学生名单

标签：

原文地址：http://blog.csdn.net/mayuko2012/article/details/46537945