Lecturer wants this as the header file:

using namespace std;

class BankAcct {
    public:
        BankAcct(int a, int b);		
        string display();				// member function to display to screen account number and pin	
		string show();
		int get_acc_num();
		int get_pin_num();
        
    private:
        int account_number;
        int pin;
};

This is what I have written:

using namespace std;

class BankAcct {
    public:
        BankAcct(int a, int b);		// constructor for bank account data.
        void display();				// member function to display to screen account number and pin	
		int get_acc_num();
		int get_pin_num();
        
    private:
        int account_number;
        int pin;
};


BankAcct::BankAcct(int a, int b):account_number(a), pin(b) {}  	// account number and pin number.

void BankAcct::display() {										// function to display account number and pin.
	cout<< endl <<"Account number: 324-001-"<< account_number <<"\n Pin code: "<< pin;
}

int BankAcct::get_acc_num() {
	return account_number;
}

int BankAcct::get_pin_num() {
	return pin;
}