//DISPLAY 4.3 A Function Definition
#include <iostream>
using namespace std;

//### Define a function #####################3
//Computes the total cost, including 5% sales tax,
//on number_par items at a cost of price_par each.
double total_cost(int number_par, double price_par)
{
    const double TAX_RATE = 0.05; //5% sales tax
    double subtotal;

    subtotal = price_par * number_par;
    return (subtotal + subtotal*TAX_RATE);
}

int main( )
{
    double price, bill;
    int number;

    cout << "Enter the number of items purchased: ";
    cin >> number;
    cout << "Enter the price per item $";
    cin >> price;

    //calling/evoking total_cost function, passing number and price's values
    //as argument, and storing value returned by the function to bill 
    bill = total_cost(number, price);

    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(2);
    cout << number << " items at "
         << "$" << price << " each.\n"
         << "Final bill, including tax, is $" << bill
         << endl;

    return 0;
}