строка — C ++ Создание книжного магазина, синтаксическая ошибка

Ошибка, которую я получаю, есть C3867 'Member::getMN': non-standard syntax; use '&' to create a pointer to member', Та же ошибка для getID, nBks, стоимости и стоимости.

Запрашивая у клиентов фамилию и идентификационный номер, затем количество книг, которые они хотят, и запрашивая стоимость этой книги. Должен показать всю информацию. Не уверен, где моя ошибка на самом деле.

#ifndef MEMBER_H
#define MEMBER_H
#include <string>
#include <iostream>

using namespace std;

// define the class members and member function prototypes here
class Member
{
private:
string MemberName;//customer name
string MemberID;//customer id
int numBooks=0;//number of books
double PurchaseAmt=0;//cost of books

public:
void setMN(string);
void setmID(string);
void setnBks(int);
void setcost(double);
string getMN() const;
string getID()const;
int nBks()const;
double cost()const;//cost of a book
double tcost()const;
};
#endif

#include "member.h"   // Needed for the member class
#include <iostream>      // Needed for cout
#include <cstdlib>       // Needed for the exit function
using namespace std;

void Member::setMN(string name)//string size for membername
{   if (name.size() < 12)
MemberName = name.substr(0, 12);
else
{
cout << "Invalid Member ID\n";
system("pause");
exit(EXIT_FAILURE);
}
}

void Member::setmID(string ID)//string size for MemberID
{   if (ID.size() < 5)
MemberID = ID.substr(0,5);
else
{
cout << "Invalid Member ID\n";
system("pause");
exit(EXIT_FAILURE);
}

}
void Member::setnBks(int num)//check for number of books
{   if (num > 0)
numBooks = num;
else
{
cout << "Invalid book count, must be over 0.\n";
system("pause");
exit(EXIT_FAILURE);
}
}

void Member::setcost(double amount)//check for cost of the book.
{   if (amount > 0)
PurchaseAmt = amount;
else
{
cout << "Invalid cost, can not be less then 0.\n";
system("pause");
exit(EXIT_FAILURE);
}
}string Member::getMN() const
{   return MemberName;
}

string Member::getID() const
{   return MemberID;
}

int Member::nBks() const
{   return numBooks;
}

double Member::cost() const
{   return PurchaseAmt;
}

double Member::tcost() const//getting the total cost of the book(s)
{   return numBooks * numBooks;

}

#include <iostream>
#include <string>
#include <iomanip>
#include "member.h"  // Needed for Member class

using namespace std;

void getinfo(Member&);
void display(Member);

int main()
{
Member books;

system("pause");
return 0;
} // end main

//this function returns member name and id, also number of books and the cost.
// this function displays the book store's data.
void getinfo(Member& x)
{
string MemberName, MemberID;
int numBooks;
double PurchaseAmt;

cout << fixed << showpoint << setprecision(2);

cout << "What is the members last name, must be under 12 char?\n";
cin >> MemberName;
x.setMN(MemberName);

cout << "What is the members ID, must be under 5 int?\n";
cin >> MemberID;
x.setmID(MemberID);

cout << "How many books?\n";
cin >> numBooks;
x.setnBks(numBooks);

cout << "How much does each book cost?\n";
cin >> PurchaseAmt;
x.setcost(PurchaseAmt);

} // end getting information.

void display(Member x)
{
cout << fixed << showpoint << setprecision(2);
cout << "The member's last name is : " << x.getMN << endl;
cout << "The member's ID is : " << x.getID << endl;
cout << "The number of books bought are : " << x.nBks << endl;
cout << "The cost per book is : " << x.cost << endl;
cout << "The total is : " << x.tcost << endl;

}