C++ Trouble Inputting Data into Private Vector (invalid use) - c++

Question

I have a vector of class "Account". It's private to a class BankingSystem. Here's how I have them defined.
Account Class:
struct newAccount
{
string firstName;
string lastName;
string accountPass;
int accountID;
float accountBalance;
}; //end of structure newAccount
class Account
{
string firstName;
string lastName;
string accountPass;
int accountID;
float accountBalance;
private:
int depositAmount;
int withdrawAmount;
public:
static newAccount createAccount( int, float, string, string, string ); //creates new account
void deposit( int ); //deposits money into account
void withdraw(int); //withdrawals money from account
int retdeposit() const; //function to return balance amount
friend class BankingSystem;
}; //end of class Account
BankingSystem Class:
class BankingSystem
{
int accountID;
char fileName;
private:
std::vector<Account> accounts_;
public:
static void addAccount();
static void storeAccount( newAccount );
void deleteAccount();
void accountInquiry();
void saveAccounts();
void loadAccountsFromFile();
friend class Account;
}; // end of class BankingSystem
I'm trying to store new accounts in the vector in this manner.
1) addAccount function in BankingSystem.h
void BankingSystem::addAccount()
{
int ID;
float balance;
std::string pass, first, last;
cout << "\n\t Enter the Account ID: ";
cin >> ID;
cout << "\n\t Enter the passcode: ";
cin >> pass;
cout << "\n\t Enter Client's first name: ";
cin >> first;
cout << "\n\t Enter Client's last name: ";
cin >> last;
cout << "\n\t Enter starting balance: ";
cin >> setw(6) >> balance;
storeAccount( Account::createAccount( ID, balance, pass, first, last ) );
return;
}
2) createAccount in Account.h
newAccount Account::createAccount( int ID, float balance, string first, string last, string pass )
{
newAccount a;
a.accountID = ID;
a.accountBalance = balance;
a.firstName = first;
a.lastName = last;
a.accountPass = pass;
return a;
}
3) storeAccount in BankingSystem.h
void BankingSystem::storeAccount( newAccount a )
{
accounts_.push_back(a);
}
Everything is working fine except storing data in the vector. The line accounts_.push_back(a); has this error; "invalid use of member 'accounts_' in static member function."

Answer 1

A static method does not have access to a class instance (no this) so inside of storeAccount and addAccount the member accounts_ does not exist.
FYI: nothing after a return statement will be executed so the line cout << "\n\t Account ID: " << a.accountID << " added successfully."; is rather useless in your current code.
Consider the following implementation for reference:
using namespace std;
class Account
{
private: // data members
string firstName;
string lastName;
string accountPass;
int accountID;
float accountBalance;
public:
// constructor that initializes members
Account(int id, float bal, const string& fname, const string& lname, const string& pass)
: accountID(id), accountBalance(bal), firstName(fname), lastName(lname), accountPass(pass) {}
}; //end of class Account
class BankingSystem
{
private: // data members
int accountID;
char fileName;
vector<Account> accounts_;
public:
void addAccount()
{
int ID;
float balance;
string pass, first, last;
// prompt input, initialize values, etc
// construct a new Account from values and add it to vector
accounts_.push_back(Account(ID, balance, first, last, pass));
}
void storeAccount( const Account& newAccount )
{
// add an already initialized account
accounts_.push_back(newAccount);
}
}; // end of class BankingSystem

Answer 2

A static member function doesn't have any special access to member variables like accounts_.
addAccount and storeAccount are static member functions. You must have made them so for a reason but it was a mistake. Remove that static and you will remove this error. I'm guessing you'll then have a different problem. If so ask another question and find out the right way to solve that.

Answer 3

The method is static, so it has no "this" pointer, so it has no idea what object you want to access the accounts_ variable of. Also, you will never see that printout on createAccount() because it's after the return call.