Question

I wanted to pass an object - which is also a vector - through a function using pointers.

I believe the issue arises on line 75 (transaction(&user, userID);) where I attempt to pass the object "user" through to the function "transaction". I don't believe the classes are relevant so I left them out. Thank you so much in advance. Here is the source.cpp code:

void transaction(vector<Customer *> &user, int userID);

void newAccount(vector<Customer*> & user, int userID);

void intr(vector<Customer*> & user, int userID, int account, int interest);

void loans(vector<Customer*> & user, int userID, int account, int loan);

int main()
{

    vector<Customer> user(3);

    user[0].setname("Josh");
    user[0].setID(1);
    user[0].bank[0].setbalance(100);
    user[0].bank[1].setbalance(101);
    user[0].bank[0].setoverdraft(200);
    user[0].bank[1].setoverdraft(201);
    user[0].accounts = 1;
    user[0].setpin(1202);

    user[1].setname("John");
    user[1].setID(2);
    user[1].bank[0].setbalance(102);
    user[1].bank[0].setoverdraft(202);
    user[1].accounts = 0;
    user[1].setpin(1203);

    user[2].setname("Jack");
    user[2].setID(3);
    user[2].bank[0].setbalance(103);
    user[2].bank[0].setoverdraft(203);
    user[2].accounts = 0;
    user[2].setpin(1204);

    int input;
    int userID;
    int pin;
    int account;
    bool menu = true;

    //Menu
    while (menu)
    {
        cout << " - Enter '1' to display all customer names and ID's." << endl;
        cout << " - Enter '2' for further transactions." << endl;
        cout << " - Enter '3' to make a quick withdrawal of " << char(156) << "10 from an account." << endl;
        cout << " - Enter '4' to exit." << endl;
        cin >> input;

        // List
        if (input == 1)
        {
            for (int i = 0; i < user.size(); i++)
            {
                cout << "[Name: " << user[i].getname() << "\t" << "ID: " << user[i].getID() << "]" << endl;
            }
            cout << endl;
        }
        // Transactions
        else if (input == 2)
        {
            cout << "Enter Customer ID: ";
            cin >> userID;
            cout << "Enter pin: ";
            cin >> pin;
            if (pin == user[userID].getpin())
            {
                transaction(&user, userID);
            }
            else { cout << "Pin invalid." << endl; }
        }
        // Quick withdrawal
        else if (input == 3)
        {   
            cout << "Enter Customer ID: ";
            cin >> userID;
            cout << "Enter pin: ";
            cin >> pin;
            cout << "Enter the account you wish to make a withdrawal from: ";
            cin >> account;
            if (pin == user[userID].getpin())
            {
                if (account <= user[userID].accounts)
                {
                    if (user[userID].bank[account].getbalance() - 10 <= -user[userID].bank[account].getoverdraft())
                    {
                        user[userID].bank[account].withdraw(10);
                    }
                    else { cout << "Insignificunt funds. Overdraft limit (" << char(156) << user[userID].bank[account].getoverdraft() << ")" << endl; }

                }
                else { cout << "That account does not exist." << endl; }
            }
            else { cout << "Pin invalid." << endl; }
        }
        // Exit
        else if (input == 4)
        {
            menu = false;
        }
    }

    return 0;
    }

    void transaction(vector<Customer *> &user, int userID){...}

ERROR DESCRIPTION: initial value of reference to non-const must be an lvalue.

Answer 1

您将错误的参数传递给transaction()第一个参数引用客户指针的向量

std::vector<Customer*> &user

但是您传递了地址的客户

vector<Customer> user(3);
transaction(&user, userID);

您应该将vector<Customer>
更改为vector<Customer*> user(3)。

或

改变void transaction(vector<Customer *> &user, int userID);
至void transaction(vector<Customer> &user, int userID);

如果你做同样的事情，其他功能也是如此。

关于错误，你确定这是问题吗？

How do you pass an object through a function using a pointer?

1 个答案: