Rajan_sust's blog

Safest way for comparing double numbers.
By Rajan_sust, history, 8 years ago, In English

Chek the link: https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/

  • Vote: I like it
  • +12
  • Vote: I do not like it

»
7 years ago, # |
  Vote: I like it 0 Vote: I do not like it

code: https://paste.ubuntu.com/25515182/

→ Reply
  • »
    »
    7 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Why wouldn't lessThan be a < b + eps and lessThanEqual be a <= b + eps?

    → Reply
  • »
    »
    7 years ago, # ^ |
      Vote: I like it +13 Vote: I do not like it

    In your code (and in code in the post) there are a lot of constructions like this:

    if (A == B)
    return true;
return false;

    Do you know that they should be written like this:?

    bool c = (A == B);
if ((c == true) == true) 
    return true;
else if ((c == true) == false)
    return false;
else assert(c == true || c == false);
    → Reply
    • »
      »
      »
      7 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it 
      if (A == B)
    return true;
return false;

      And what's wrong? It's more readable than return A == B

      → Reply
      • »
        »
        »
        »
        7 years ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        It's code with excess branching, it can't be more readable. When you use if-else, it means that you have some different behaviour based on the condition. But when you need just return result of condition, like in these cases with a simple comparison, you should write as it is: return condition;.

        It's really a basic and famous example of how you can make your code dirtier with such return true/false and I don`t understand how you can say that it is more readable.

        → Reply
        • »
          »
          »
          »
          »
          7 years ago, # ^ |
            Vote: I like it +3 Vote: I do not like it

          It's really a basic and famous example how to write beautiful and readable code:

          if (very_long_condition_1)
  return true;
if (very_long_condition_2)
  return true;
return false;

          I bet you will write return very_long_condition_1 || very_long_condition_2 and someone will refactor it eventually.

          → Reply
          • »
            »
            »
            »
            »
            »
            7 years ago, # ^ |
              Vote: I like it 0 Vote: I do not like it

            At first, A == B is not a very_long_condition.

            At second, I will not.

            The post and code from the comment have only single-comparison conditions. So it's a very bad attempt from you to try say that I can't balance between shortness and readability in that way =)

            → Reply
    • »
      »
      »
      7 years ago, # ^ |
        Vote: I like it +3 Vote: I do not like it

      I always like Sarcasm public.

      → Reply