I am currently working on a banking service project, on a beginner level. I am thinking to cut down on how I have passed ‘Customer’ class’s cust object’s reference as a parameter in each method of each class, in a way so that I am able to NOT pass ‘Customer’ class’s object for a function definition.

class accounts;
class transactions;
class Customer;
class BankingServices;

class accounts
{
    public:
    int acc_no;
    std::string acc_password;

    public:
    void details(Customer& cust) const
    {
        std::cout << "Your Account number is: " << cust.acc.acc_no << std::endl;
        std::cout << "Your Account password is: " << cust.acc.acc_password << std::endl;
    }

    void add();

    void bal(Customer& cust);
};

class transactions
{
    public:
    int transHis[3];

    public:

    transactions()
    {
        transHis[3] = {0};
    }

    void transfer(int amt, int to_acc_no, Customer& cust);

    void withdraw(int amt, Customer& cust);

    void deposit(int amt, Customer& cust);

    void updateHis(int amt, Customer& cust);

    void showTransHis(Customer& cust);
};

class Customer
{
    public:
    std::string name;
    accounts acc;
    transactions trans;
    
    public:
    Customer()
    {

    }

    void details() const
    {
        std::cout << "Your Account number is: " << this->acc.acc_no << std::endl;
    }

    void create_cust(Customer& cust); // adds a customer and it's details into the database(it has add_acc() as a sub function)
};

class BankingServices
{
    public:
    Customer cust;

    public:
    BankingServices()
    {
        int val;
        std::cout << "Press 1 to create an account, if not a customer and don't have an account." << std::endl;
        std::cout << "Press 2 to enter account details ,if already a customer. " << std::endl;
        // taking input for 'val' and checking
        val = chkInputValfor2(&val);

        if (val == 1)
        {
            this->cust.create_cust(this->cust);
        }
        else 
        {
            std::cout << "Enter your first name: ";
            std::cin >> this->cust.name;

            std::cout << "Enter your Account Number: ";
            std::cin >> this->cust.acc.acc_no;
            
            std::cout << "Enter your Password: ";
            std::cin >> this->cust.acc.acc_password;
        }
    }

    void services()
    {
        int val;
        std::cout << "Enter 1 to withdraw money                 " << "Enter 2 to deposit money" << std::endl;
        std::cout << "Enter 3 to transfer money                 " << "Enter 4 to check acccount balance" << std::endl;
        std::cout << "Enter 5 to see transaction history        " << "Enter 6 to fetch account details" << std::endl;
        std::cin >> val;

        if (val == 1)
        {
            int amt;
            std::cout << "Enter Amount to be withdrawn: ";
            std::cin >> amt;
            this->cust.trans.withdraw(amt, this->cust);
        }
        else if (val == 2)
        {
            int amt;
            std::cout << "Enter amount to be deposited: ";
            std::cin >> amt;
            this->cust.trans.deposit(amt, this->cust);
        }
        else if (val == 3)
        {
            int amt, to_acc_no;
            std::cout << "Enter amount to be transfered: ";
            std::cin >> amt;
                    std::cout << std::endl;

            std::cout << "Enter account number to reciever: ";
            std::cin >> to_acc_no;
            std::cout << std::endl;

            this->cust.trans.transfer(amt, to_acc_no, this->cust);
        }
        else if (val == 4)
        {
            this->cust.acc.bal(this->cust);
        }
        else if (val == 5)
        {
            this->cust.trans.showTransHis(this->cust);
        }
        else if (val == 6)
        {
            this->cust.acc.details(this->cust);
        }
        else
        {
            std::cout << "Wrong input! Enter again" << std::endl;
            services();
        }
    }
};

I thought of using inheritance but that didn’t work. I thought inheriting customer class in accounts, transactions, BankingServices class would help, but it didn’t. May be there is something i did wrong. I am expecting a way somehow I need not to pass the cust object’s reference for every function.