#include <iostream>
using namespace std;

int main()
{

int froyoStamps = 0;

while (1)
{

char userSelection = ' ';


//print menu
cout << "Press P to purchase Froyo" << endl;
cout << "Press S to stop" << endl;
cin >> userSelection;

    if (input == 'P' || input == 'p')
    {
        int froyoPurchase;

        //freebies
        if //(eligible for freebies)
        {
            char freeAnswer = ' ';

            cout << "You are eligible for a free yogurt." << endl;
            cout << "Would you like one? Yes/No: "
            cin >> freeAnswer;

            if (freeAnswer == 'y' || freeAnswer == 'Y')
            {
                stamps -= 10;
            }

            if (freeAnswer == 'n' || freeAnswer == 'N')
            {
                //go to transaction
            }

            //error check
            else ()
            {
                //error message
                //next loop pass
            }
        }

        //transaction
        cout << "How many Fro-yos would you like to buy: ";
        cin >> froyoPurchase;

        if (//froyoPurchase is a valid number)
        {
            continue to free item check
        }

        //transaction error check
        if invalid number
        {
            "you fucked up"
            exit
        }



        if if they aren't eligible for freebies
        {
        go back to menu
        }
    }

    if (input == 's' || input == 'S')
    {
        cout << "You pressed 'S'. Goodbye." << endl;
        //exit
    }

    else
    {
        cout << "ERROR." << endl;
        //exit
    }
}
}