c++编程题输入30名学生数据包括学号和成绩,并按成绩升序输出全部学生成绩表

Answer 1

//= =这是第几个学生了…
#include <iostream>
#include <vector>
#include <algorithm>
class Student{
    friend std::istream& operator >> (std::istream&,Student&);
    friend std::ostream& operator << (std::ostream&,Student&);
public:
    Student() = default;
    Student(const std::string& i, double sco):_id(i), _score(sco){ }
    double score() const {return _score;}
    const std::string& id() const {return _id;}
private:
    double _score = .0;
    std::string _id;
};
std::istream& operator >> (std::istream& is, Student& stu)
{
    if(is)
        is >> stu._id >> stu._score;
    else
        stu = Student();
    return is;
 }
std::ostream& operator << (std::ostream& os, Student& stu)
{
    os << stu._id << " " << stu._score;
    return os;
}
int main()
{
    std::vector<Student> students;
    //这里做个测试，你自己加上输入输入输出吧 (^^)/
    std::string id = "000001";
    double score = 1.0;
    for(std::size_t i = 0; i< 30; ++i) ï½›
        students.push_back({id, score++});
        ++id[id.find_last_not_of('9')];
    ï½
    //升序排序
    std::stable_sort(students.begin(), students.end(),
                              []
                              (const Student& s1, const Student& s2)
                              -> bool
                                 {
                                   if(s1.score() > s2.score())
                                       return true;
                                    return false;  
                                 });
    for( auto stu : students )
        std::cout << stu << std::endl;
    return 0;
}