Thread: Nice use for the conditonal operaror

Hi I came across a nice use for conditional operator. I always hated dealing text for "You have 1 units" or "You have 2 units" - ie, dealing with plural for single items.

Code:

int main(void)
{
  const double unit_price = 3.50;   /* unit price in euro */
  const double discount1 = 0.05;    /* discount for more than 10 */
  const double discount2 = 0.10;    /* discount for more than 20 */
  const double discount3 = 0.15;    /* discount for more than 50 */
  double total_price = 0.0;
  int quantity = 0;

  printf("\nWelcome to the shop. Basic unit costs %.2f. Discounts available.",unit_price);
  printf("\n5%% off on more than 10. 10%% off on more than 20. 15%% off on more than 50!");
  printf("\nEnter the number of units you want to buy: ");
  scanf("%d",&quantity);

  total_price = quantity*unit_price*(1.0 -
                  (quantity>50 ? discount3 : (
                     quantity>20 ? discount2 : (
                       quantity>10 ? discount1 : 0.0))));

  printf("The price for %d unit%s is %.2f euro.\n", quantity, quantity>1 ? "s" : "", total_price);
  /* quantity>1 check shows how to deal single or plural units */
  return 0;
}

The code segment:

Code:

quantity, quantity>1 ? "s" : ""

is pretty cool. It's one in my bookmarks. I love that! Going back I always neglected the shorthand conditional op.

Welcome to the shop. Basic unit costs 3.50. Discounts available.
5% off on more than 10. 10% off on more than 20. 15% off on more than 50!
Enter the number of units you want to buy: 1
The price for 1 unit is 3.50 euro.

in printf it increases readability...
but in total_price calculations - I prefer if/else for readability...

Code:

coeff = 1.0;
if(quantity>50 ) coeff -= discount3 ;
else if (quantity>20 ) coeff -= discount2;
else if (quantity>10 ) coeff -= discount1;

total_price = quantity*unit_price*coeff;

for me is a lot more easier to understand than the original code

Keep in mind that 0 should also be plural, but your check is for >1. 1 is the only case in which it is not plural.

0 dollars
1 dollar
2 dollars

Also bear in mind, that if you come to translate this code into other languages, a simple search for all strings isn't going to work so well.

as well as 21 dollar should be singular