请大家帮忙看看这个C++写的学生成绩单管理系统？？？
不知道哪里出错了， 感觉是文件读和写那一块出了问题， 调试了很久都没找出来；主要问题是当"学生成绩单.txt"还没有建立的时候（就是第一次运行该程序）， 调试过程中数据显示，修改这块都还是正常， 但是当关闭程序，再次打开程序，运行测试时，在GetList（）函数处，从文件读数据时， 学生的名字就开始乱码了，当然显示，修改这些函数就没法做了，请明白的人说一说阿 。。感激不敬。
student.h///#include<iostream>
#include<string>
using namespace std;
class Student
{
public:
Student(){}
void InputData(); //学生数据输入；
void LinkData(Student *s); //链接学生数据；
void ShowData(); //显示学生数据；
string Getname(); //取姓名；
long Getnumber(); //取学号；
float Getscores(); //取成绩；
Student &AlterName(); //修改姓名；
Student &AlterNumber(); //修改学号；
Student &AlterScores(); //修改成绩；
Student *next;
private:
string name;
long number;
float scores;
};
void Student::ShowData(void)
{
cout<<"姓名\t学号\t成绩:"<<endl;
cout<<name<<"\t"<<number<<"\t"<<scores<<endl;
}
void Student::InputData()
{
cout<<"请输入学生数据:"<<endl;
cout<<"姓名:"<<endl;
cin>>name;
cout<<"学号:"<<endl;
cin>>number;
cout<<"成绩:"<<endl;
cin>>scores;
}
void Student::LinkData(Student *s)
{
next = s;
}
string Student::Getname()
{
return name;
}
long Student::Getnumber()
{
return number;
}
float Student::Getscores()
{
return scores;
}
Student &Student::AlterName()
{
string new_name;
cout<<"请输入新名字:"<<endl;
cin>>new_name;
name = new_name;
return *this;
}
Student &Student::AlterNumber()
{
long new_number;
cout<<"请输入新学号:"<<endl;
cin>>new_number;
number = new_number;
return *this;
}
Student &Student::AlterScores()
{
float new_scores;
cout<<"请输入新成绩:"<<endl;
cin>>new_scores;
scores = new_scores;
return *this;
}
//学生成绩单.cpp
#include<fstream>
#include"student.h"
int Menu(void); //主菜单函数；
int FindofName(void); //以姓名方式查询函数；
int FindofNumber(void); //以学号方式查询；
int Find(void); // 查询函数；
Student *GetList(void); // 读文件，建立链表；
void save(Student *head); //写文件，存数据；
int Change(void); //修改学生数据；
int Del(void); //删除学生数据；
int Print(void); //打印学生成绩单；
int Add(void); //添加学生数据；
void Sort(void); //排序学生成绩；
int FindofName(void)
{
string findname;
cout<<"请输入要查找学生的姓名:"<<endl;
cin>>findname;
Student *head, *p;
p = head = GetList();
while(head)
{
if (head->Getname() == findname)
{
head->ShowData();
break;
}
head = head->next;
}
if (!head)
{
cout<<"对不起，没有该学生!"<<endl;
}
free(p);
return 0;
}
int FindofNumber(void)
{
long findnumber;
cout<<"请输入要查找学生的学号:"<<endl;
cin>>findnumber;
Student *head, *p;
p = head = GetList();
while(head)
{
if (head->Getnumber() == findnumber)
{
head->ShowData();
break;
}
head = head->next;
}
if (!head)
{
cout<<"对不起，没有该学生!"<<endl;
}
free(p);
return 0;
}
int Find(void)
{
cout<<"1.按姓名查找"<<endl;
cout<<"2.按学号查找"<<endl;
cout<<"0.退出"<<endl;
int choice;
while(1)
{
cout<<"请选择查询方式:"<<endl;
cin>>choice;
switch(choice)
{
case 1:
FindofName();
break;
case 2:
FindofNumber();
break;
case 0:
return 0;
default:
cout<<"选择错误!"<<endl;
}
}
return 0;
}
Student *GetList(void)
{
Student *head = NULL, *p1 = NULL ,*p2 = NULL;
ifstream fromfile("学生成绩单.txt", ios_base::in|ios_base::binary);
p1 = new Student;
fromfile.read((char *)p1, sizeof(Student));
p2 = p1;
while(!fromfile.eof())
{
if (NULL == head)
{
head = p2 = p1;
}
else
{
p2->next = p1;
p2 = p1;
}
p1 = new Student;
fromfile.read((char *)p1, sizeof(Student));
}
p2->next = NULL;
free(p1);
fromfile.close();
return head;
}
void save(Student *head)
{
ofstream tofile("学生成绩单.txt", ios_base::app|ios_base::binary);
Student *p1 = head;
while(p1)
{
tofile.write((char*)(p1), sizeof(Student));
p1 = p1->next;
}
tofile.close();
free(head);
}
int Change(void)
{
Student *head, *p;
head = p = GetList();
string name;
cout<<"请输入姓名:"<<endl;
cin>>name;
while(p)
{
if (p->Getname() == name)
{
cout<<"请问要修改学生什么数据:"<<endl;
cout<<"1.姓名"<<endl;
cout<<"2.学号"<<endl;
cout<<"3.成绩"<<endl;
cout<<"0.修改完毕!"<<endl;
int choice;
while(1)
{
cout<<"请选择:"<<endl;
cin>>choice;
switch(choice)
{
case 1:
p->AlterName();break;
case 2:
p->AlterNumber();break;
case 3:
p->AlterScores();break;
case 0:
save(head);
return 0;
default:
cout<<"选择错误!"<<endl;
}
}
break;
}
p = p->next;
}
if (!p)
{
cout<<"对不起，没有该学生!"<<endl;
}
save(head);
return 0;
}
int Del(void)
{
Student *head, *p1 = NULL , *p2 = NULL;
head = GetList();
string name;
cout<<"请输入需删除学生的姓名:"<<endl;
cin>>name;
p1 = head;
while(p1)
{
if (head->Getname() == name) //删除为头结点；
{
head = head->next;
break;
}
else
{
if (p1->Getname() == name)
{
p2->next = p1->next;
break;
}
}
p2 = p1;
p1 = p1->next;
}
if (!p1)
{
cout<<"对不起，没有该学生!"<<endl;
}
save(head);
free(p1);
return 0;
}
void Sort(void)
{
float max;
Student *head = NULL, *p1 = NULL, *p2 = NULL, *newhead = NULL, *p3 = NULL, *p4 = NULL;
head = GetList();
while(1)
{
p1 = head;
if(NULL == head)
{
break;
}
p1 = head;
max = head->Getscores();
while(1)
{
if(p1->next != NULL)
{
p1 = p1->next;
}
if(max < p1->Getscores())
{
max = p1->Getscores();
}
if(p1->next == NULL)
{
break;
}
}
p1 = head;
while(max != p1->Getscores())
{
p2=p1;
p1=p1->next;
}
if(p1 == head)
{
head = head->next;
}
else
{
p2->next = p1->next;
}
if(newhead == NULL)
{
p3 = newhead = p1;
}
else
{
p4 = p3;
p3 = p1;
p4->next = p3;
}
}
cout<<"成绩排列如下:"<<endl;
p1 = newhead;
while(newhead)
{
newhead->ShowData();
newhead = newhead->next;
}
free(p1);
}
int Add(void)
{
Student *head = NULL, *p1 = NULL, *p2 = NULL;
int N;
cout<<"请问要输入几个学生数据:"<<endl;
cin>>N;
for (int i = 0; i < N; i ++)
{
p1 = new Student;
p1->InputData();
if (NULL == head)
{
head = p2 = p1;
}
else
{
p2->next = p1;
p2 = p1;
}
}
p2->next = NULL;
save(head);
free(p1);
return 0;
}
int Print(void)
{
Student *head, *p;
head = p = GetList();
if(!p)
{
cout<<"文件为空!"<<endl;
}
while(p)
{
p->ShowData();
p = p->next;
}
free(head);
return 0;
}
int Menu(void)
{
cout<<"*****************"<<"欢迎进入学生成绩管理系统！"<<"*****************"<<endl;
int n;
cout<<"1.查询某学生成绩"<<endl;
cout<<"2.修改某学生成绩"<<endl;
cout<<"3.删除某学生成绩"<<endl;
cout<<"4.增加某学生成绩"<<endl;
cout<<"5.打印学生成绩单"<<endl;
cout<<"6.排序学生成绩单"<<endl;
cout<<"7.退出"<<endl;
while (1)
{
cout<<"请从主菜单中选择："<<endl;
cin>>n;
switch(n)
{
case 1:
Find();
break;
case 2:
Change();
break;
case 3:
Del();
break;
case 4:
Add();
break;
case 5:
Print();
break;
case 6:
Sort();
break;
case 7:
return 0;
break;
default:
cout<<"选择错误！"<<endl;
}
}
return 0;
}
int main(void)
{
ofstream tofile("学生成绩单.txt", ios_base::app|ios_base::binary); // 若没有文件，建立文件；
tofile.close();
Menu();
return 0;
}
