学生成绩管理系统，求助，帮忙看看怎么改
各位大神求帮忙~~成绩排序运行不了，不会改~~总成绩改成平均分也不会#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
class student
{
friend class studentMessage;
student *next;
char name[30];
char num[30];
double score[6];
public:
student()
{
strcpy(name, "null");
strcpy(num, "null");
for (int i = 0; i < 6; ++i) score[i] = 0;
}
student(const student &a)
{
strcpy(name, a.name);
strcpy(num, a.num);
for (int i = 0; i < 6; ++i)
score[i] = a.score[i];
}
student &input()
{
cout << "姓名："; cin >> name;
cout << "学号："; cin >> num;
for (int i = 0; i < 5; ++i)
{
cout << "输入第" << (i + 1) << "门成绩:";
cin >> score[i];
score[5] += score[i];
}
return *this;
}
student* get_next()
{
return next;
}
void print()
{
printf("%8s %10s ", name, num);
for (int i = 0; i < 6; ++i) printf(" %6.2f ", score[i]);
printf("\n");
}
void Swap()
{
char temp[30];
strcpy(temp, name);
strcpy(name, next->name);
strcpy(next->name, temp);
strcpy(temp, num);
strcpy(num, next->num);
strcpy(next->num, temp);
for (int i = 0; i < 6; ++i)
{
int tmp = score[i];
score[i] = next->score[i];
next->score[i] = tmp;
}
}
};
class studentMessage
{
protected:
student *first;
student *last;
public:
studentMessage()
{
first = last = new student;
}
~studentMessage()
{
Clear();
delete first;
}
studentMessage &Append();
student *Find(const char *x);
void Query();
studentMessage &Delete();
studentMessage &Clear();
studentMessage &Sort();
void print();
int menu();
};
studentMessage &studentMessage::Append()
{
student x;
x.input();
student *ptr = last;
*ptr = x;
last = new student;
ptr->next = last;
return *this;
}
studentMessage &studentMessage::Delete()
{
char x[30];
cout << "输入要删除的信息（学号或姓名）\n";
cin >> x;
student *ptr = Find(x);
if (ptr == last)
{
cout << "未找到相关信息\n";
return *this;
}
ptr->print();
cout << "是否删除此信息？（是输入1，否输入0）";
cin >> x;
if (*x == '1')
{
if (ptr == first)
{
first = first->next;
delete first;
}
else
{
student *temp = first;
while (temp->next != ptr) temp = temp->next;
temp->next = ptr->next;
delete ptr;
}
cout << "已删除\n";
}
else
{
cout << "已取消\n";
}
return *this;
}
studentMessage &studentMessage::Clear()
{
char ch[30];
cout << "将删除所有信息。确认请按Y";
cin >> ch;
if (*ch != 'Y' && *ch != 'y')
{
cout << "已取消\n";
return *this;
}
student *ptr = first;
while (ptr != last)
{
student *next = ptr->next;
delete ptr;
ptr = next;
}
first = last;
return *this;
}
void studentMessage::print()
{
if (first == last)
{
cout << "暂无信息\n";
return ;
}
cout << "---------------------------------成绩列表------------------------------" << endl;
cout << "序号 姓名 学号 成绩1 成绩2 成绩3 成绩4 成绩5 总成绩" << endl;
int no = 1;
student *ptr = first;
while (ptr != last)
{
printf("%3d:", no++);
ptr->print();
ptr = ptr->next;
}
}
student *studentMessage::Find(const char *x)
{
student *ptr = first;
while (ptr != last)
{
if (strcmp(ptr->name, x) == 0 || strcmp(ptr->num, x) == 0)
break;
ptr = ptr->next;
}
return ptr;
}
void studentMessage::Query()
{
char x[30];
cout << "输入你要查询的信息(学号或姓名)";
cin >> x;
student *ptr = Find(x);
if (ptr == last)
{
cout << "没有查询到相关信息\n";
}
else
{
ptr->print();
}
}
studentMessage &studentMessage::Sort()
{
int x;
cout << "输入你想按照哪门课的成绩来排序?((1-5)总成绩输入6):";
cin >> x;
x--;
student *ptr, *cnt = last;
while (cnt != first)
{
ptr = first;
while (ptr->next != cnt)
{
if (ptr->next->score[x] > ptr->score[x])
{
ptr->Swap();
}
ptr = ptr->next;
}
cnt = ptr;
}
return *this;
}
int studentMessage::menu()
{
cout << "===============================\n";
cout << " 学生成绩管理系统\n\n";
cout << " 1.添加信息\n";
cout << " 2.显示所有学生成绩\n";
cout << " 3.查询信息\n";
cout << " 4.删除信息\n";
cout << " 5.成绩排序\n";
cout << " 6.删除所有信息\n";
cout << " 0.退出\n";
cout << "===============================\n";
int ch;
cin >> ch;
return ch;
}
int main()
{
studentMessage ls;
int ch;
while (ch = ls.menu())
{
switch(ch)
{
case 2: ls.print(); break;
case 1: ls.Append(); break;
case 3: ls.Query(); break;
case 4: ls.Delete(); break;
case 5: ls.Sort(); break;
case 6: ls.Clear(); break;
}
}
return 0;
}
