我正在制作一个程序来保存银行信息（即帐户、密码、余额）。我遇到了某个错误，但我不确定原因。
这是整个代码。
#include <iostream>
#include <string>
#include <fstream>
#include <cstdlib>
using namespace std;
int x = 0;
void addUser();
void login();
void deposit();
void withdrawl();
struct bankUser
{
double balance;
string account, password;
};
bankUser user[20];
int menu()
{
ofstream myfile("bankmachine.txt", ios::app);
char choice;
cout << "1) Add account" << endl;
cout << "2) Log in" << endl;
cout << "3) Make deposit" << endl;
cout << "4) Make withdrawl" << endl;
cout << "5) Quit" << endl << endl;
cout << "What would you like to do?: ";
cin >> choice;
cout << endl;
switch (choice)
{
case '1':
addUser();
break;
case '2':
login();
break;
case '3':
deposit();
break;
case '4':
withdrawl();
break;
case '5':
myfile << user[x].balance << endl;
myfile.close();
cout << "Thank you for using the banking system." << endl << endl;
system ("pause");
return 0;
break;
default:
cout << "That is not a valid option. Please choose again." << endl << endl;
menu();
}
}
void addUser()
{
if ((x >= 0) && (x < 20))
{
cout << "Please enter your desired account name: ";
cin >> user[x].account; // Account name.
cout << "Thank you, now please enter your desired password: ";
cin >> user[x].password; // Account password.
cout << "\nAccount created. You may now log in." << endl << endl;
ofstream myfile("bankmachine.txt", ios::app); // Opens the text file at the end of the file (if data is already present).
myfile << user[x].account << endl; // Writes to text file.
myfile << user[x].password << endl; // ^
myfile.close(); // Close text file (important).
x++; // Increases to simulate the addition of another user.
menu();
}
else // Will display if user has entered 20 users.
{
cout << "You have entered the maximum number of users." << endl;
menu();
}
}
void deposit()
{
int deposit;
string answer;
do
{
cout << "Please enter the amount of money that you would like to deposit: ";
cin >> deposit;
user[x].balance += deposit;
cout << "Thank you. Your new balance is " << user[x].balance << "." << endl << endl;
cout << "Would you like to make another deposit? (Y/N): ";
cin >> answer;
} while ((answer != "N") && (answer == "Y"));
cout << endl;
menu();
}
void withdrawl()
{
int withdraw;
string answer;
do
{
cout << "Please enter the amount of money that you would like to withdraw: ";
cin >> withdraw;
if (withdraw <= user[x].balance)
{
user[x].balance -= withdraw;
}
else
{
cout << "\nSorry, you do not have sufficient funds to complete this withdrawl.\nPlease try again." << endl << endl;
withdrawl();
}
cout << "Thank you. Your new balance is " << user[x].balance << "." << endl << endl;
cout << "Would you like to make another withdrawl? (Y/N): ";
cin >> answer;
} while (answer != "N" && answer == "Y");
cout << endl;
menu();
}
void login() // Function to log in.
{
string user, pw, usernameCheck, passwordCheck;
double balance;
cout << "Please enter your login information." << endl << endl;
cout << "Account name: ";
cin >> user;
cout << "Password: ";
cin >> pw;
cout << endl;
ifstream myfile("bankmachine.txt", ios::app);
while (!myfile.eof()) // Loops until end of file.
{
getline(myfile, usernameCheck);
if (usernameCheck == user)
{
getline(myfile, passwordCheck);
if (passwordCheck == pw)
{
myfile >> balance;
cout << "Login successful." << endl;
cout << "Your balance is " << balance << "." << endl << endl;
user[x].balance = balance;
}
else // If not, display:
{
cout << "Password incorrect." << endl << endl;
}
}
}
myfile.close(); // Close text file (important).
menu();
}
int main()
{
cout << "Welcome to the banking system." << endl << endl;
menu();
}
我不断收到此错误（第 172 行）：
request for member 'balance' in 'user.std::basic_string<_CharT, _Traits,
_Alloc>::operator[] [with _CharT = char, _Traits = std::char_traits<char>, _Alloc =
std::allocator<char>](((unsigned int)x))', which is of non-class type 'char'|
这是什么原因造成的？我该如何解决？任何答案表示赞赏。