为什么我输入新建信息以后，打开TXT文本查看，

里面的信息除了几个汉字以外什么都没有呢？

求教

#include <iostream.h>
#include <fstream.h>
#include <string.h>

//基类
class person
{
public:
 person();
 char name[20];
 char sex;
 int age;
};
person::person(){}
//学生类
class student: public person
{
public:
 student();
 void xinjian();
 void xiugai();
 void shanchu();
 char ID[10];
 char pro[20];
 int rank;
};

 //老师类
class teacher: public person
{
public:
 teacher();
 void xinjian1();
 void xiugai1();
 void shanchu1();
 char num[10];
 char com[20];
 char subject[20];
};

teacher::teacher(){};
teacher tea[100];
student stu[100];
ofstream outfile("f1.txt",ios::app|ios::nocreate);
student::student(){}

 //新建学生信息
void student::xinjian()
{  
 int i=0,a;
 do
 {
 cout<<"请输入新建学生信息："<<endl;
 cout<<"输入姓名:";
 cin>>stu[i].name;
 cout<<"输入性别:";
 cin>>stu[i].sex;
 cout<<"输入年龄:";
 cin>>stu[i].age;
 cout<<"输入学号:";
 cin>>stu[i].ID;
 cout<<"输入专业:";
 cin>>stu[i].pro;
 cout<<"输入排名:";
 cin>>stu[i].rank;
 i++;
 outfile<<"姓名"<<stu[i].name<<"    "<<"性别"<<stu[i].sex<<"    "<<"年龄"<<stu[i].age<<"    ";
 outfile<<"学号"<<stu[i].ID<<"    "<<"专业"<<stu[i].pro<<"        "<<"排名"<<stu[i].rank<<endl;
 cout<<"数据录入成功，是否继续录入，选择是请按1，否请按0:";
 cin>>a;
 }while(a==1);
}

//新建老师信息
void teacher::xinjian1()
{  
 int i=0,a;
 do
 {
 cout<<"请输入新建老师信息："<<endl;
 cout<<"输入姓名:";
 cin>>tea[i].name;
 cout<<"输入性别:";
 cin>>tea[i].sex;
 cout<<"输入年龄:";
 cin>>tea[i].age;
 cout<<"输入工号:";
 cin>>tea[i].num;
 cout<<"输入单位名称:";
 cin>>tea[i].com;
 cout<<"输入教授课程:";
 cin>>tea[i].subject;
 i++;
 outfile<<"姓名"<<tea[i].name<<"    "<<"性别"<<tea[i].sex<<"    "<<"年龄"<<tea[i].age<<"    ";
 outfile<<"工号"<<tea[i].num<<"    "<<"单位名称"<<tea[i].com<<"    "<<"教授课程"<<tea[i].subject<<endl;
 cout<<"数据录入成功，是否继续录入，选择是请按1，否请按0:";
 cin>>a;
 }while(a==1);
}

//修改学生信息
void student::xiugai()
{
 char num[20];
 int i=0,a;
 bool enter=0;
 do
 {
 cout<<"请输入您要修改的学生的学号:";
 cin>>num;
  do
  {
   if(strcmp(num,stu[i].ID)==0)
   {
    enter=1;
    break;
   }
   else i++;
  }while(enter==0,i<100);
  if(enter==1)
  {
   cout<<"请出入改正后的学生信息:"<<endl;
   cout<<"输入姓名:";
   cin>>stu[i].name;
   cout<<"输入性别:";
   cin>>stu[i].sex;
   cout<<"输入年龄:";
   cin>>stu[i].age;
   cout<<"输入学号:";
   cin>>stu[i].ID;
   cout<<"输入专业:";
   cin>>stu[i].pro;
   cout<<"输入排名:";
   cin>>stu[i].rank;
   cout<<"数据修改成功";
  }
  if(enter==0)
   cout<<"你输入的学号有误，请检查后重新输入:"<<endl;
 cout<<"是否继续修改，是请按1，否请按0:";
 cin>>a;
 }while(a==1);
}
   //修改老师信息
void teacher::xiugai1()
{
 char number[20];
 int i=0,a;
 bool enter=0;
 do
 {
 cout<<"请输入您要修改的老师的工号:";
 cin>>num;
  do
  {
   if(strcmp(number,tea[i].num)==0)
   {
    enter=1;
    break;
   }
   else i++;
  }while(enter==0,i<100);
  if(enter==1)
  {
   cout<<"请出入改正后的老师信息:"<<endl;
   cout<<"输入姓名:";
   cin>>tea[i].name;
   cout<<"输入性别:";
   cin>>tea[i].sex;
   cout<<"输入年龄:";
   cin>>tea[i].age;
   cout<<"输入工号:";
   cin>>tea[i].num;
   cout<<"输入单位名称:";
   cin>>tea[i].com;
   cout<<"输入教授课程:";
   cin>>tea[i].subject;
   cout<<"数据修改成功";
  }
  if(enter==0)
   cout<<"你输入的工号有误，请检查后重新输入:"<<endl;
 cout<<"是否继续修改，是请按1，否请按0:";
 cin>>a;
 }while(a==1);
}