我用c++语言来做文件操作，例如写入和读出的操作，但是当输入完数据之后，就进入死循环了，请各位高手帮忙

#include "stdafx.h"#include<fstream.h>#include"iostream.h"#include"stdlib.h"void enter(char *filename){ char name[30],flag=✀y✀; int number,score; ofstream outstuf; outstuf.open(filename,ios::out); if(!outstuf) {cerr<<"file could not be open"<<endl; abort(); } outstuf<<"this is a file of students尀n"; cout<<"请输入： number ,name ,an score: (enter Ctrl+z to end intput)尀n"; while (cin>>number>>name>>score) { outstuf<<number<<✀尀t✀<<name<<✀尀t✀<<score<<✀尀n✀; } outstuf.close(); }void display(char*filename){ char name[30]; int number,score; ifstream instuf(filename,ios::in); if(!instuf) {cerr<<"file could not be open"<<endl; abort(); } char s[80]; instuf.getline(s,80); while(instuf>>number>>name>>score) {cout<<number<<✀尀t✀<<name<<✀尀t✀<<score<<✀尀n✀; } instuf.close();}void interfaced(void){ cout<<"文件复习:尀n"; cout<<"=======================================尀n"; cout<<" 输入纪录-----------------0尀n"; cout<<" 查询纪录-----------------1尀n"; cout<<" 退出---------------------2尀n"; cout<<"=======================================尀n"; cout<<"请输入数字(0--2):尀n";}void main(){for(;;){ char filename[30]; int i; cout<<"please input the name of student`s file"<<endl; cin>>filename; interfaced(); cin>>i; switch(i) { case 0: enter(filename); break; case 1: display(filename); break; case 2: exit(0); default : cout<<"警告!!!请输入数字0-2!尀n"; ) }}} 问题补充：我用for语句主要是想当把数据输入完之后，再回到主界面，然后继续其他操作，如:显示操作,如果不用for我就不用在这问这问题了，因为我也试过，不用for就直接输入完数据就结束了。 //我用的环境是VC6.0。//“i”不是定义为整型数据吗？会变成ASCII的50？//