compiling error

[BtheMan]

I keep getting a error on this project for school im doing can someone look over it and see what is wrong that im missing also can you help me with where to put the command to freeze the application after its done cause i dont know where to put system("pause"); on this problem.
"The payroll manager at Gerston Blankets wants a program that calculates and displays the gross pay for
each of the company’s employees. It also should calculate and display the total gross pay. The payroll
manager will enter the number of hours the employee worked and his or her pay rate. Employees
working more than 40 hours should receive time and one-half for the hours over 40. Use a void function
to determine an employee’s gross pay. Use a value-returning func-tion to accumulate the total gross
pay. The program should display the total gross pay only after the payroll manager has finished entering
the data for all the employees. Use a sentinel value to end the program."

#include <iostream>  
#include <iomanip>
#include <cmath>  

using namespace std;

double getGrossPay(double hrsWrk, double payRate);

int main()
{
	// declare variables  
	double hrsWrk = 0.0;
	double payRate = 0.0;
	double totalGrossPay = 0.0;
	char   sentinel = ' ';

	// prime the loop  
	cout << "Do you have hours to enter? Y/N  (N to stop): ";
	cin >> sentinel;

	system("pause");
	return 0;

	while (toupper(sentinel) == 'Y')
	{
		cout << "Enter hours worked:\n";
		cin >> hrsWrk;
		cout << "Enter pay rate:\n";
		cin >> payRate;

		// call function for individual gross pay
		double grossPay;

		getGrossPay(hrsWrk, payRate, grossPay);

		totalGrossPay += GetTotalGrossPay(grossPay);


		// Display information  
		cout << fixed << setprecision(2);
		cout << "grossPay:$" << grossPay << endl;
		cout << "Do you have any more hours to enter? (Y/N):" << endl;
		cin >> sentinel;
	}


	cout << "totalGrossPay:$" << totalGrossPay << endl;

}

void getGrossPay(double hrsWrk, double payRate, double& grossPay)
{
	// calculates and returns the gross Pay 

	if (hrsWrk <= 40)
	{
		grossPay = hrsWrk * payRate;
	}
	else
	{
		grossPay = (hrsWrk - 40) * (payRate * 1.5) + (40 * payRate);
	}
}

double GetTotalGrossPay(double grossPay)
{
	return grossPay;

}

[JayhawkZombie]

Well, you should put the return statement after your while loop for one.

GetTotalGrossPay is not declared before it is used, so you should add a declaration for it like you did for the other. It doesn't do anything, though. If you don't need it then just get rid of it altogether.