/* Exercise 4.19 Solution */
#include <stdio.h>

main()
{
  int product, quantity;
  float total = 0.0;

  printf("Enter pairs of item numbers and quantities.\n");
  printf("Enter -1 for the item number to end input.\n");

  while (1) 
    {
      scanf("%d", &product);
      
      if (product == -1)
        break;
      
      scanf("%d", &quantity);

      switch (product) 
        {
        case 1:
          total += quantity * 2.98;
          break;
        case 2:
          total += quantity * 4.50;
          break;
        case 3:
          total += quantity * 9.98;
          break;
        case 4:
          total += quantity * 4.49;
          break;
        case 5:
          total += quantity * 6.87;
          break;
        default:
          printf("Invalid product code:  %d\n", product);
          printf("            Quantity:  %d\n", quantity);
        }
    }

  printf("The total retail value was:  %.2f\n", total);
  return 0;
}