请各位大哥看看这个c++的问题

我想有c++编一个普通的“银行管理系统”，并且把它写进文件，但是出现一些问题，或者思路也有问题，希望大虾们帮我看看并改正，谢谢~！
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#include"iostream.h"
#include"iomanip.h"
#include"string.h"
#include"stdlib.h"
#include"fstream.h"
#define N 1000000000
class bank
{
protected:
        struct node
        {
         int account;
         int mima;
         float money;
        }fn[N];
public:
        bank()
        {   int i;
                fstream file("bank.txt",ios::in);
                while(1)
                {   for(i=0;i<=N;i++)
                {
                        file.read((char *)&fn[i].account,sizeof(fn[i].account));
                        file.read((char *)&fn[i].mima,sizeof(fn[i].mima));
                        file.read((char *)&fn[i].money,sizeof(fn[i].money));
                        if(!file) break;
                }
                }
                file.close();
        }
void newaccount()//新建帐户
{
int i,b,bb;float c;
for(i=0;i<=N;i++)
{
cout<<"Please input the mima:"<<endl;
cin>>bb;
cout<<"Please input the mima again:"<<endl;
cin>>b;
cout<<"Please input the startmoney:"<<endl;
cin>>c;
if(bb!=b) cout<<"The mima is error!"<<endl;
else{
fn[i++].account;
fn[i].mima=b;
fn[i].money=c;
}
}
}
void findaccount()///查找
{
int a,b,bb,i;
for(i=0;i<=N;i++)
{
  cout<<"Please input your account:"<<endl;
  cin>>a;
  if(a!=fn[i].account) cout<<"The account is error!"<<endl;
  else
  {
   cout<<"Please input the mima:"<<endl;
   cin>>bb;
   cout<<"Please input the mima again:"<<endl;
   cin>>b;
   if(b!=bb||b!=fn[i].mima) cout<<"The mima is error!"<<endl;
   else
   {
    cout<<setw(10)<<"account"<<setw(10)<<"leftmoney"<<endl;
        cout<<setw(10)<<fn[i].account<<setw(10)<<fn[i].money<<endl;
   }
  }

}
}
void changmima()//修改密码
{
int a,b1,bb1,bb2,b2,i;
for(i=0;i<=N;i++)
{
  cout<<"Please input your account:"<<endl;
  cin>>a;
  if(a!=fn[i].account) cout<<"The account is error!"<<endl;
  else
  {
   cout<<"Please input the mima:"<<endl;
   cin>>bb1;
   cout<<"Please input the mima again:"<<endl;
   cin>>b1;
   if(b1!=bb1||b1!=fn[i].mima) cout<<"The mima is error!"<<endl;
   else
   {
    cout<<"Please input the newmima:"<<endl;
        cin>>bb2;
    cout<<"Please input the newmima again:"<<endl;
    cin>>b2;
        if(bb2!=b2) cout<<"The mima is error!"<<endl;
        else fn[i].mima=b2;
   }
  }
}
}
void inmoney()//存款
{
int a,b,bb,i;float c;
for(i=0;i<=N;i++)
{
  cout<<"Please input your account:"<<endl;
  cin>>a;
  if(a!=fn[i].account) cout<<"The account is error!"<<endl;
  else
  {
   cout<<"Please input the mima"<<endl;
   cin>>bb;
   cout<<"Please input the mima again:"<<endl;
   cin>>b;
   if(bb!=b||b!=fn[i].mima) cout<<"The mima is error!"<<endl;
   else
   {
    cout<<"Please input the inmoney:"<<endl;
        cin>>c;
        fn[i].money+=c;
   }
  }
}
}
void outmoney()//取款
{
int a,b,bb,i;float c;
for(i=0;i<=N;i++)
{
  cout<<"Please input your account:"<<endl;
  cin>>a;
  if(a!=fn[i].account) cout<<"The account is error!"<<endl;
  else
  {
   cout<<"Please input the mima"<<endl;
   cin>>bb;
   cout<<"Please input the mima again:"<<endl;
   cin>>b;
   if(bb!=b||b!=fn[i].mima) cout<<"The mima is error!"<<endl;
   else
   {
    cout<<"Please input the outmoney:"<<endl;
        cin>>c;
        if(c>=fn[i].money) cout<<"Sorry! The money of account is little!"<<endl;
        else fn[i].money-=c;
   }
  }
}
}
void zhuanmoney()//转帐
{
int a1,a2,b1,bb1,i;float c;
struct node fn_1[N];
for(i=0;i<=N;i++)
{
  cout<<"Please input your account:"<<endl;
  cin>>a1;
  if(a1!=fn[i].account) cout<<"The account is error!"<<endl;
  else
  {
   cout<<"Please input the mima:"<<endl;
   cin>>bb1;
   cout<<"Please input the mima again:"<<endl;
   cin>>b1;
   if(bb1!=b1||b1!=fn[i].mima) cout<<"The mima is error!"<<endl;
   else
   {
    cout<<"Please input the other account:"<<endl;
        cin>>a2;
        if(a2!=fn_1[i].account) cout<<"the account is error!"<<endl;
        else
        {cout<<"Please input the outmoney"<<endl;
        cin>>c;
        if(c>=fn[i].money) cout<<"Sorry,the money is little!"<<endl;
        else
        {
         fn[i].money-=c;
         fn_1[i].money+=c;
        }
        }
   }
  }
}
}
void quit()
{char tomenu;
cout<<"请按'q'或'Q'返回"<<endl; //返回主菜单提示
do{
        cin>>tomenu;
}while(!(tomenu=='q'||tomenu=='Q'));return ;
}

~bank()
{
        fstream file("bank.txt",ios::out);
        for(int i=0;i<=N;i++)
                if(fn[i].account==0&&fn[i].mima==0&&fn[i].money==0)
                {
                 file.write((char *)&fn[i].account,sizeof(fn[i].account));
                 file.write((char *)&fn[i].mima,sizeof(fn[i].mima));
                 file.write((char *)&fn[i].money,sizeof(fn[i].money));
                }
                file.close();
}

};
void main()
{
bank f1;
int select;
while(1)
{
cout<<setw(5)<<"********************************************************************"<<endl;
cout<<setw(15)<<"欢迎使用3_209银行帐户管理系统!"<<endl;
cout<<setw(15)<<"(版权归209用户所有,禁止非法盗用,否则我们很生气，后果很严重!)"<<endl;
cout<<setw(5)<<"********************************************************************"<<endl;
cout<<"创建新帐户请选：1"<<endl<<"查帐请选：2"<<endl<<"存款请选：3"<<endl<<"取款请选：4"<<endl<<"转帐请选：5"<<"修改密码请选: 6"<<endl<<"退出请选: 7"<<endl;
do
{
cin>>select;
}while(select==1||select==2||select==3||select==4||select==5||select==6||select==7);
  switch(select)
{
  case '1':
          f1.newaccount();break;
  case '2':
      f1.findaccount();break;
  case '3':
          f1.inmoney();break;
  case '4':
          f1.outmoney();break;
  case '5':
          f1.zhuanmoney();break;
  case '6':
          f1.changmima();break;
  case '7':
          f1.quit();
}

}
}
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希望大哥们耐心讲解下

[此贴子已经被作者于2005-6-23 11:17:47编辑过]