/******************************************
 *
 * This program demonstrates the use of modulus and
 * division function, and the general programming style.
 * 
 * Author: Xiannong Meng
 * Date:   June 7, 2001
 *
 ******************************************
*/

#include <iostream>

using namespace std;

const double SALES_TAX_RATE = 0.0875;    // 8.75% sales tax

int coinChange(int &, int);                // function prototype

void main(void)
{
    int    amountPaid,             // amount paid to the seller
           itemCost,               // how much it costs
           amount2Return,          // 'change' to the customer
           quarters2Return,
           dimes2Return,           // number of dimes to return
           nickles2Return,          // number of nickles to return
           pennies2Return,         // number of pennies to rerun
           totalCost;              // final cost = item cost + tax

    cout << " Specify the cost (in cents e.g. 536 means 5 dollars 36 cents) : ";
    cin >> itemCost;
    cout << " Specify amount paid (in cents) : ";
    cin >> amountPaid;

    /* calculate the total cost in cents */
    totalCost = int((itemCost * (1 + SALES_TAX_RATE)) + 0.5);

    /* calculate the change */
    amount2Return = amountPaid - totalCost;

    /* print a message to the user */
    cout << " Total cost (sales tax incl.) : " << totalCost << endl;
    cout << " Amount remitted : " << amountPaid << endl;
    cout << " Amount to return : " << amount2Return << endl;

    /* out of the amount to return, calculate how many quarters */
    quarters2Return = coinChange(amount2Return, 25);

    /* how many dimes? */
    dimes2Return = coinChange(amount2Return, 10);

    /* how many nickles? */
    nickles2Return = coinChange(amount2Return, 5);

    /* finally how many pennies */
    pennies2Return = coinChange(amount2Return, 1);

    /* print out the results */
    cout << " Quarters returned : " << quarters2Return << endl;
    cout << " Dimes returned : " << dimes2Return << endl;
    cout << " Nickles returned : " << nickles2Return << endl;
    cout << " Pennies returned : " << pennies2Return << endl;
}

/*
 * function : int coinChange(int & change, int coinValue)
 *            calculates the number of coins of a given face value
 *            if the amount of change and the coin face value are given
 * input: 1) int change, amount of change
 *        2) int coinValue, face value of the coin
 * output:1) the number of coins to make up the change, returned
 *           through function heading
 *        2) the change amount, through reference parameter
 */
int coinChange(int & change, int coinValue)
{
    int numOfCoins;

    numOfCoins = change / coinValue;
    change     = change % coinValue;
   
    return numOfCoins;
}