/*
题目：学生成绩管理系统
功能：学生成绩管理系统，每个学生是一个记录，包括学号，姓名，性别，3门课程成绩。系统
要求实现以下功能：
1、信息录入：录入学生成绩信息（包括学生学号、姓名、各门课程的成绩等）；
2、信息查询：输入学号，查询学生各门课程的成绩，并显示。
3、排序：按各门课程的成绩平均分进行排序，并显示。
4、信息删除与修改——输入学号，删除该学生的成绩信息。
*/
#include<iostream>
#include <string>
#include<iomanip>
using namespace std;
class StudentData
{//建立学生类
public:
string name; double average;
double math, english, chinese, chemistry, biology, physics, number;
StudentData *next;
StudentData *pre;
void insertdate()
{ cin >> chinese >> math >> english >> physics >> chemistry >> biology; }
void setlang() { cin >> chinese; }
void setmath() { cin >> math; }
void setenglish() { cin >> english; }
void setphysics() { cin >> physics; }
void setchemistry() { cin >> chemistry; }
void setbiology() { cin >> biology; }//输入各科成绩
} ;
struct linklist
{//带头指针和尾指针的双向链表
StudentData *head, *present;//头指针和当前指针
void insert_one();
void delete_data();
void setdata();
bool check();
void creat();
void output();
void setmore();
void averagerank();
}X;
void linklist::output()
{//打印链表，输出学生信息
cout << " 姓名 学号 语文 数学 英语 物理 化学 生物 平均分" << endl;
present = head;
while (present->next != NULL)
{//不取尾结点，尾节点为空
present->average = (present->chinese + present->math + present->english + present->physics + present->chemistry + present->biology) / 6;
cout << setw(12)<< present->name << setw(12) << present->number << setw(8) << present->chinese << setw(8) << present->math << setw(8) << present->english
<< setw(8) << present->physics << setw(8) << present->chemistry << setw(8) << present->biology << setw(16) << present->average <<endl;
present = present->next;
}
}
void linklist::creat()
{//创建空结点
present = new StudentData;
head = present;
present->next = NULL;
present->pre = NULL;
}
void linklist::insert_one()
{
present = new StudentData;
head->pre = present;
present->next = head;
head = present;
present->pre = NULL;//新加一个学生数据加在表头
cout << "请输入学生姓名: ";
cin >> present->name;
cout << "请输入学号：";
cin >> present->number;
cout << "请一次输入语文，数学，英语，物理，化学，生物各科成绩：" << endl;
present->insertdate(); //输入成绩
}
void linklist::delete_data()
{//删除学生信息
//string studentnam;
int sigh = 0;
cout << "请输入要删除的学生学号： ";
if (check())
{
if (present->pre == NULL)
{
head = present->next;
delete present;
present = head;
}
if (present->pre != NULL)
{
present->pre->next = present->next;
present->next->pre = present->pre;
head = present->pre;
delete present;
}
cout << "删除数据成功！" << endl;
}
else cout << "删除失败。" << endl;
}
bool linklist::check()
{//按学号查找并输出学生信息
present = head;
int idnumber;
cin >> idnumber;
while (present->next != NULL)
{
if (idnumber == present->number)
{
present->average = (present->chinese + present->math + present->english + present->physics + present->chemistry + present->biology) / 6;
cout << " 姓名 学号 语文 数学 英语 物理 化学 生物 平均分" << endl;
cout << setw(12) << present->name << setw(12) << present->number << setw(8) << present->chinese << setw(8) << present->math << setw(8) << present->english
<< setw(8) << present->physics << setw(8) << present->chemistry << setw(8) << present->biology << setw(16) << present->average << endl;
return true;
}
else
{
present = present->next;
continue;
}
}
cout << "查无此人！" << endl;
return false;
}
void linklist::setdata()
{//修改学生成绩
int subject;
cout << "请输入学生的学号: ";
if (check())
{ while (1)
{//设置个循环修改成绩，按0或者超出选项退出循环
cout << " 1.语文 2.数学" << endl
<< " 3.英语 4.物理" << endl
<< " 5.化学 6. 生物" << endl
<< " 0.返回上级菜单 " << endl;
cout << "请输入需要修改的科目编号及成绩: ";
cin >> subject;
switch (subject)
{
case 1:present->setlang();break;
case 2:present->setmath();break;
case 3:present->setenglish();break;
case 4:present->setphysics();break;
case 5:present->setchemistry();break;
case 6:present->setbiology();break;
case 0:cout << "回到上级菜单" << endl;;return;
default:
{
cout << "回到上级菜单。" << endl;//这行可以不要
return;
}
}
cout << "修改成功！" << endl;
}
}
}
void linklist::setmore()
{//通过循环次数来控制插入人数
cout << "请输入添加学生人数： ";
int n;
cin >> n;
while (n--) insert_one();
}
void linklist::averagerank()
{//注意链表的尾结点是默认值，因为在创建链表的时候是在空节点上逆序创建的
int h = 0, k = 0; present = head;
L:
while (present->next->next != NULL)
{
h = k;
if (present->average <= present->next->average)
{
present = present->next;
}//无需互换
if (present->average > present->next->average&&present->pre == NULL)
{
k++;
present->next = present->next->next;
present->next->pre->next = present;
present->pre = present->next->pre;
present->next->pre = present;
present->pre->pre = NULL;
}//头节点处链表间互换
if(present->average > present->next->average&&present->pre != NULL)
{
if (present->next->next != NULL)
{//最后一个空结点不纳入考虑
k++;
present->pre->next = present->next;
present->next = present->next->next;
present->pre->next->next = present;
present->pre->next->pre = present->pre;
present->pre = present->pre->next;
present->next->pre = present;
}
}
while (h != k)
{//若一次完整循环下来没有顺序变化，退出
while (present->pre != NULL) { present = present->pre; } goto L;
}
}
while (present->pre != NULL) { present = present->pre; }
head = present;//因为头结点不为空，修改完后可能会被改变，此处从新定位头结点
cout << " 姓名 学号 语文 数学 英语 物理 化学 生物 平均分" << endl;
do{
present->average = (present->chinese + present->math + present->english + present->physics + present->chemistry + present->biology) / 6;
cout << setw(12) << present->name << setw(12) << present->number << setw(8) << present->chinese << setw(8) << present->math << setw(8) << present->english
<< setw(8) << present->physics << setw(8) << present->chemistry << setw(8) << present->biology << setw(16) << present->average << endl;
present = present->next;
} while (present->next != NULL);
}
int main()
{
cout << " " << endl;
cout << " 学生信息管理系统 " << endl;
cout << " " << endl;
cout << " 1.添加一个学生信息 2.查询学生信息" << endl;
cout << " 3.删除学生信息 4.将学生信息列表输出" << endl;
cout << " 5.修改学生成绩 6.批量输入任意个数学生信息" << endl;;
cout << " 7.按各门成绩平均分进行排序 0.退出系统 " << endl;
cout << " " << endl;
X.creat();//先建空表
while (true) {
int choise;
cout << endl<<"请输入相应操作序号： " ;
cin >> choise;
switch (choise)
{
case 1: X.insert_one();break;
case 2:
{
cout << "请输入查询学生的学号： ";
X.check(); break;
}
case 3: X.delete_data();break;
case 4: X.output();break;
case 5: X.setdata();break;
case 6: X.setmore();break;
case 7: X.averagerank();break;
case 0:
break;
default:
cout << "对不起，有关功能正在开发！" << endl;break;
}
if (!choise) break;
}
return 0;
}