1

我必须创建一个银行系统程序，它可以添加、删除、查找、保存到文件等。为此，我需要使用与下面的私有数据成员匹配的 Vector，建议使用 push_back() 函数添加新的帐户。

我能想出从提示中获取数据到向量（没有编译错误）的唯一方法是为 Account 创建一个构造函数，其中包含 int accountID、int passcode、string firstname、string lastname、double balance。然后，此构造函数使用 set() 函数使用列出的相同名称初始化帐户中的所有私有数据成员。

问题是当我使用 accounts_.size() 函数查看向量是否发生变化时，它总是输出 1。

如何让向量将每个附加值输入到向量中？

更不用说在尝试任何矢量函数时我总是会遇到编译错误......

在不写出实际代码的情况下，你们都能为我指明正确的方向吗？谢谢！

----edit - 在下面添加了 main.cpp 和一个发布编译错误的 cout 循环示例

我遇到的问题是无论我输入数据多少次，大小都保持不变..所以当它编译时，它似乎没有将数据输入到向量中。

此外，当我尝试查看向量中的内容时，我会收到编译错误：

bankingsys.cpp(36): warning C4018: '<' : signed/unsigned mismatch
bankingsys.cpp(37): error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'Account' (or there is no acceptable conversion)
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(679): could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const char *)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(726): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,char)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(764): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const char *)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(811): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,char)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(937): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const signed char *)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(944): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,signed char)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(951): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const unsigned char *)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(958): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,unsigned char)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(968): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>,Account>(std::basic_ostream<_Elem,_Traits> &&,_Ty)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>,
1>              _Ty=Account
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(1085): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const std::error_code &)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(186): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ostream<_Elem,_Traits> &(__cdecl *)(std::basic_ostream<_Elem,_Traits> &))'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(192): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ios<_Elem,_Traits> &(__cdecl *)(std::basic_ios<_Elem,_Traits> &))'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(199): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::ios_base &(__cdecl *)(std::ios_base &))'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(206): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::_Bool)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(226): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(short)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(260): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned short)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(280): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(int)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(305): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned int)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(325): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(345): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned long)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(366): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__int64)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(386): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned __int64)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(407): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(float)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(427): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(double)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(447): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long double)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(467): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(const void *)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(487): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_streambuf<_Elem,_Traits> *)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>
1>          ]
1>          while trying to match the argument list '(std::ostream, Account)'
1>
1>Build FAILED.
4

2 回答 2

1

问题出在你的案例陈述中......

  switch ( inputcode )
  {     
  case 1:// Add Account
      {
      BankingSystem add;
      add.accAdd();
      }
      break;

  case 2:// Delete Account
      {
      BankingSystem del;
      del.accDelete();
      }
      break;

  case 3:// Account Inquiry
      {
      BankingSystem inquire;
      inquire.accInquiry();
      }
      break;        

  case 4: // Save Accounts to File
      {
      BankingSystem save;
      save.accSave();
      }
      break;

  case 5: // Load Accounts from File
      {
      BankingSystem load;
      load.accLoad();
      }
      break;

您BankingSystem在每个 case 语句中创建和使用类的新实例，而不是使用您在main()函数开头创建的实例。这就是为什么你总是得到 1size()的原因。你想用你的myBankingSystem指针来代替......

  switch ( inputcode )
  {     
  case 1:// Add Account
      myBankingSystem->accAdd();
      break;

  case 2:// Delete Account
      myBankingSystem->accDelete();
      break;

  case 3:// Account Inquiry
      myBankingSystem->accInquiry();
      break;        

  case 4: // Save Accounts to File
      myBankingSystem->accSave();
      break;

  case 5: // Load Accounts from File
      myBankingSystem->accLoad();
      break;
于 2012-08-09T01:37:28.597 回答
1

如果您的代码无法编译，我不知道您如何在运行时遇到问题:) 从您发布的内容来看，该行

cout << accounts_[i];

不起作用，因为操作员 << 不知道由谁来处理 Account 类型。

当您编写 cout << something 时，编译器实际上会调用 ostream& operator<<(something) 。'something' 必须是基本类型（int、float 等...）或者您已为其定义了 ostream& operator<< 重载的类型。

所以，不用过多介绍细节，这里有 2 个简单的解决方案： - 编写一个自由函数 ostream& operator<< (ostream& out,const Account& val); 它负责逐个字段地输出帐户。

ostream& operator<< (ostream& out,const Account& val);
{
 out << val.getID() << endl;
 out << val.getPass() << endl;
 out << val.getLast() << endl;
 out << val.getFirst() << endl;
 out << val.getBalance() << endl;
}

- 编写一个方法 std::string Account::toString() 将帐户序列化为字符串，然后调用

out << accounts_[i].toString();

这将解决您的编译错误，并允许您显示 Account 实例的内容。由于向量计数始终为 1，请参阅下面 Will 的回答。

高温高压

于 2012-08-09T01:40:00.297 回答