// Program to test "totalprice" function.

#include <iostream.h>
#include <stdlib.h>		// has EXIT_SUCCESS, EXIT_FAILURE
#include <iomanip.h>		// has setiosflags, setprecision

// Pre:  N, price, taxrate all >= 0.
// Post:  return value is price-with-tax for N items costing "price"
//          each, plus sales tax at taxrate/100.
double totalprice(int N, double price, double taxrate)
{
  return N * price * (1 + taxrate/100);
}

int main(void)
{
  int N;
  double price, taxrate;
  cout << "Enter number of items, price, tax rate:\n";
  cin >> N >> price >> taxrate;
  if (N < 0 || price < 0 || taxrate < 0)
    {
      cout << "Error!  bad input.\n";
      exit(EXIT_FAILURE);
    }
  // set up to print with exactly 2 decimal places.
  cout << setiosflags(ios::showpoint | ios::fixed) << setprecision(2);
  cout << "number of items = " << N << endl;
  cout << "price per item = $" << price << endl;
  cout << "tax rate = " << taxrate << endl;
  cout << "total price = $" << totalprice(N, price, taxrate) << endl;
  return EXIT_SUCCESS;
}