学生通讯录，当我创新一个新通讯录并且输入后，一直循环输出是否继续，哪里有问题？

学生通讯录程序：用结构体和数组实现学生通讯录程序。基本信息包括学号、姓名、班级、籍贯、手机、QQ号、电子邮箱等信息。具体实现的管理功能如下：（1）输入并显示多个学生信息；（2）可实现学生信息的添加；（3）查询（至少提供按姓名和手机查询两种方式）；（4）修改（只提供按照姓名进行修改）；（5）删除（依据指定的信息删除如姓名、学号等）；（6）文件的导入和导出（从文件中读取若干条通讯录，或者将通讯录输出到文件中）。

#include<iostream>
#include<string>
#include <fstream>
using namespace std;
struct Student
    {
        int num;
        char name[20];
        char Class[20];
        char addr[30];
        int phone;
        int QQ;
        char mail[50];
        Student *next;
    };
Student *creat()
{
    int i=1;
    char n='y';
    Student *head= new Student();
    if(head==NULL)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    head->next==NULL;
    while(n=='y')
    {
        Student *newStudent= new Student();
        if(head==NULL)
        {
            cerr<<"内存空间分配失败"<<endl;
            exit(1);
        }
        cin>>newStudent->num>>newStudent->name>>newStudent->Class>>newStudent->addr>>newStudent->phone>>newStudent->QQ>>newStudent->mail;
        newStudent->next=NULL;
        newStudent->next=head->next;
        head->next=newStudent;
        i++;
        cout<<"是否继续?";
        cin>>n;
    }
    cout<<"是否继续?";
        cin>>n;
    return head;
}
bool Add(Student *head)
{
    Student *newStudent=new Student();
    if(newStudent==NULL)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    cin>>newStudent->num>>newStudent->name>>newStudent->Class>>newStudent->addr>>newStudent->phone>>newStudent->QQ>>newStudent->mail;
    newStudent->next=head->next;
    head->next=newStudent;
    return true;
}
bool Search(Student *head,char name[20],int phone)
{
    Student *p=head->next;
    while(p!=NULL&&(p->name!=name||p->phone!=phone))
    {
        p=p->next;
    }
    if(p==NULL) return false;
    return true;
}
bool Change(Student *head,int num)
{
    Student *p=head->next;
    while(p!=NULL&&(p->num!=num))
    {
        p=p->next;
    }
    int p1;char p2[20];char p3[20];char p4[30];int p5; int p6;char p7[50];
    cin>>p1>>p2>>p3>>p5>>p5>>p6>>p7;
    p->num=p1;
    p->name[20]=p2[20];p->Class[20]=p3[20];p->addr[30]=p4[30];
    p->phone=p5;p->QQ=p6;p->mail[50]=p7[20];
    if(p==NULL) return false;
    return true;
}
bool Delete(Student *head,int num)
{
    Student *pre=head;
    Student *p=head->next;
    while(p!=NULL&p->num!=num)
    {
        pre=p;
        p=p->next;
    }
    if(p==NULL) return false;
    delete p;
    p=NULL;
    return true;
}
void Print(Student *head)
{
    Student *p=head->next;
    while(p!=NULL)
    {
        cout<<"学号："<<p->num<<endl;
        cout<<"姓名："<<p->name<<endl;
        cout<<"班级："<<p->Class<<endl;
        cout<<"地址："<<p->addr<<endl;
        cout<<"电话："<<p->phone<<endl;
        cout<<"QQ:"<<p->QQ<<endl;
        cout<<"邮箱："<<p->mail<<endl;
        p=p->next;
    }
}
Student *Read()
{
    Student *head= new Student();
    if(head==NULL)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    ifstream inFile;
    inFile.open("student.txt",ios::in);
    if(!inFile.is_open())
    {
        cout<<"Error:opening file fail"<<endl;
        exit(1);
    }
    Student *newStudent =new Student();
    if(NULL==newStudent)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    while(!inFile.eof())
    {
        Student *newStudent= new Student();
        if(NULL==newStudent)
        {
            cerr<<"内存空间分配失败"<<endl;
            exit(1);
        }

        inFile>>newStudent->num>>newStudent->name>>newStudent->Class>>newStudent->addr>>newStudent->phone>>newStudent->QQ>>newStudent->mail;
        newStudent->next=head->next;
        head->next=newStudent;
    }
    inFile.close();
    return head;
}
bool Write( Student *head)
{
    Student *p=head->next;
    ofstream outFile;
    outFile.open("student.txt",ios::out);
    if(!outFile)
    {
        cout<<"Error:opening file fail"<<endl;
        exit(1);
    }
    while(p!=NULL)
    {
        outFile<<p->num<<" "<<p->name<<" "<<p->Class<<" "<<p->addr<<" "<<p->phone<<" "<<p->QQ<<" "<<p->mail<<endl;
        p->next;
    }
    return true;
}

int main() 
{
    cout<<"             请选择下面的菜单:"<<endl;
    cout<<"1 创建"<<endl;
    cout<<"2 添加"<<endl;
    cout<<"3 查询"<<endl;
    cout<<"4 修改"<<endl;
    cout<<"5 删除"<<endl;
    cout<<"6 显示"<<endl;
    cout<<"7 从文件导入"<<endl;
    cout<<"8 导出到文件"<<endl;
    cout<<"9 退出"<<endl;
    cout<<"请选择： ";
    int m;
    int num,phone;
    char name[20];
    bool finished=false;
    Student *head=NULL;
    cin>>m;
    switch(m)
    {
    case 1:
        head=creat();
        break;
    case 2:
        if(Add(head))
            cout<<"添加学生信息成功！"<<endl;
        else
            cout<<"添加学习信息失败！"<<endl;
        break;
    case 3:
        if(Search(head,name,phone))
            cout<<"搜索成功！"<<endl;
        else
            cout<<"搜索失败！"<<endl;
        break;
    case 4:
        cout<<" 请输入要修改的学生通讯录信息的学号：";
        cin>>num;
        if(Search(head,name,phone))
            cout<<"修改成功！"<<endl;
        else
            cout<<"修改失败！"<<endl;
        break;
    case 5:
        if(Delete(head,num))
            cout<<"删除成功！"<<endl;
        else
            cout<<"删除失败！"<<endl;
        break;
    case 6:
        Print(head);
    case 7:
        Read();
        break;
    case 8:
        Write(head);
        break;
    case 9:
        finished=true;
        break;
    default:
        cout<<"输入选择错误，请重新输入！"<<endl;
    }
    return 0;
}

这样不就好了吗

 
#include<iostream>
#include<string>
#include <fstream>
using namespace std;
struct Student
    {
        int num;
        char name[20];
        char Class[20];
        char addr[30];
        int phone;
        int QQ;
        char mail[50];
        Student *next;
    };
Student *creat()
{
    int i=1;
    char n='y';
    Student *head= new Student();
    if(head==NULL)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    head->next==NULL;
    while(n=='y')
    {
        Student *newStudent= new Student();
        if(head==NULL)
        {
            cerr<<"内存空间分配失败"<<endl;
            exit(1);
        }
        cin>>newStudent->num>>newStudent->name>>newStudent->Class>>newStudent->addr>>newStudent->phone>>newStudent->QQ>>newStudent->mail;
        newStudent->next=NULL;
        newStudent->next=head->next;
        head->next=newStudent;
        i++;
        cout<<"是否继续?";
        cin>>n;
    }
  //  cout<<"是否继续?";
    //    cin>>n;
    return head;
}
bool Add(Student *head)
{
    Student *newStudent=new Student();
    if(newStudent==NULL)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    cin>>newStudent->num>>newStudent->name>>newStudent->Class>>newStudent->addr>>newStudent->phone>>newStudent->QQ>>newStudent->mail;
    newStudent->next=head->next;
    head->next=newStudent;
    return true;
}
bool Search(Student *head,char name[20],int phone)
{
    Student *p=head->next;
    while(p!=NULL&&(p->name!=name||p->phone!=phone))
    {
        p=p->next;
    }
    if(p==NULL) return false;
    return true;
}
bool Change(Student *head,int num)
{
    Student *p=head->next;
    while(p!=NULL&&(p->num!=num))
    {
        p=p->next;
    }
    int p1;char p2[20];char p3[20];char p4[30];int p5; int p6;char p7[50];
    cin>>p1>>p2>>p3>>p5>>p5>>p6>>p7;
    p->num=p1;
    p->name[20]=p2[20];p->Class[20]=p3[20];p->addr[30]=p4[30];
    p->phone=p5;p->QQ=p6;p->mail[50]=p7[20];
    if(p==NULL) return false;
    return true;
}
bool Delete(Student *head,int num)
{
    Student *pre=head;
    Student *p=head->next;
    while(p!=NULL&p->num!=num)
    {
        pre=p;
        p=p->next;
    }
    if(p==NULL) return false;
    delete p;
    p=NULL;
    return true;
}
void Print(Student *head)
{
    Student *p=head->next;
    while(p!=NULL)
    {
        cout<<"学号："<<p->num<<endl;
        cout<<"姓名："<<p->name<<endl;
        cout<<"班级："<<p->Class<<endl;
        cout<<"地址："<<p->addr<<endl;
        cout<<"电话："<<p->phone<<endl;
        cout<<"QQ:"<<p->QQ<<endl;
        cout<<"邮箱："<<p->mail<<endl;
        p=p->next;
    }
}
Student *Read()
{
    Student *head= new Student();
    if(head==NULL)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    ifstream inFile;
    inFile.open("student.txt",ios::in);
    if(!inFile.is_open())
    {
        cout<<"Error:opening file fail"<<endl;
        exit(1);
    }
    Student *newStudent =new Student();
    if(NULL==newStudent)
    {
        cerr<<"内存空间分配失败"<<endl;
        exit(1);
    }
    while(!inFile.eof())
    {
        Student *newStudent= new Student();
        if(NULL==newStudent)
        {
            cerr<<"内存空间分配失败"<<endl;
            exit(1);
        }
        inFile>>newStudent->num>>newStudent->name>>newStudent->Class>>newStudent->addr>>newStudent->phone>>newStudent->QQ>>newStudent->mail;
        newStudent->next=head->next;
        head->next=newStudent;
    }
    inFile.close();
    return head;
}
bool Write( Student *head)
{
    Student *p=head->next;
    ofstream outFile;
    outFile.open("student.txt",ios::out);
    if(!outFile)
    {
        cout<<"Error:opening file fail"<<endl;
        exit(1);
    }
    while(p!=NULL)
    {
        outFile<<p->num<<" "<<p->name<<" "<<p->Class<<" "<<p->addr<<" "<<p->phone<<" "<<p->QQ<<" "<<p->mail<<endl;
        p->next;
    }
    return true;
}
int main() 
{
    cout<<"             请选择下面的菜单:"<<endl;
    cout<<"1 创建"<<endl;
    cout<<"2 添加"<<endl;
    cout<<"3 查询"<<endl;
    cout<<"4 修改"<<endl;
    cout<<"5 删除"<<endl;
    cout<<"6 显示"<<endl;
    cout<<"7 从文件导入"<<endl;
    cout<<"8 导出到文件"<<endl;
    cout<<"9 退出"<<endl;
    cout<<"请选择： ";
    int m;
    int num,phone;
    char name[20];
    bool finished=false;
    Student *head=NULL;
    cin>>m;
    switch(m)
    {
    case 1:
        head=creat();
        break;
    case 2:
        if(Add(head))
            cout<<"添加学生信息成功！"<<endl;
        else
            cout<<"添加学习信息失败！"<<endl;
        break;
    case 3:
        if(Search(head,name,phone))
            cout<<"搜索成功！"<<endl;
        else
            cout<<"搜索失败！"<<endl;
        break;
    case 4:
        cout<<" 请输入要修改的学生通讯录信息的学号：";
        cin>>num;
        if(Search(head,name,phone))
            cout<<"修改成功！"<<endl;
        else
            cout<<"修改失败！"<<endl;
        break;
    case 5:
        if(Delete(head,num))
            cout<<"删除成功！"<<endl;
        else
            cout<<"删除失败！"<<endl;
        break;
    case 6:
        Print(head);
    case 7:
        Read();
        break;
    case 8:
        Write(head);
        break;
    case 9:
        finished=true;
        break;
    default:
        cout<<"输入选择错误，请重新输入！"<<endl;
    }
    return 0;
}