display 0 in my proggram??

[ChungTong]

my program display 0 after run after i enter the loan money, rates and year
thank you for your helps
please point out my errors, i am a beginning C++programer:

#include<iostream>
using namespace std;
#include <iomanip>
#include <cmath>
class loan{
private:
double rates;
double amount;
double payment;
double totalloan;
double percent;
int years;
public:
double annualInterestRate(double);
int NumberOfYears(int);
double loanAmount(double);
double monthlypayment;
double getannualInterestRate(double);
int getNumberOfYears(int);
double getloanAmount(double);
double setannualInterestRate(double);
double setNumberOfYears(int);
double setloanAmount(double);
double getMonthlyPayment(double);
double getTotalPayment(double);
};
double loan::setannualInterestRate(double rates){
return rates;
}
double loan::setNumberOfYears(int years){
return years;
}
double loan::setloanAmount(double amount){
return amount;
}
double loan::getannualInterestRate (double percent) {
return percent;
}
int loan::getNumberOfYears(int years){
return years;
}
double loan::getloanAmount(double money){
return money;
}
double loan::getMonthlyPayment(double payment){
return payment=((1 +percent)* amount)/years;
}
double loan::getTotalPayment(double totalloan){
return totalloan=payment*years;
}
int main()
{
int years;
double annualInterestRate;
double loanAmount;
double payment;
double totalloan;
cout<<" Enter the loan Amount";
cin>>loanAmount;
cout<<" Enter the annuak interest rate of the loan:";
cin>>annualInterestRate;
cout<<" Enter the number of years for the loan";
cin>>years;
cout<<" your monthly payment is "<<payment<<".";
cout<< "Your total payment is"<< totalloan<<endl;
}

[1vD3vCM9]

You need to create an object for a class.
Read about classes.
When you create a class, you need to make an object in order to use the functions and variables.

Like this:

loan myLoan;
std::cin >> myLoan.payment;

EDIT:
I noticed that you made your payment and rates variables private, make them public to access them or make a public function that sets the variables.