Quick question on rounding :-)

[[Gandalf]]

code:

put 5 + 0.1 + 0.01 = 0.01 + 0.01 + 5 %false

I don't get it... It IS false, since one of the numbers is 0.1, and the other is 0.01. So what's so special about this?

[beard0]

[Gandalf] wrote:

code:

put 5 + 0.1 + 0.01 = 0.01 + 0.01 + 5 %false

I don't get it... It IS false, since one of the numbers is 0.1, and the other is 0.01. So what's so special about this?

You know what he meant... or at least, if you read the rest of the topic you do.

[wtd]

rizzix wrote:

No not all languages... Languages like Haskell should not have such a problem.. In haskell the floating points are represented differently.

Are you sure?

code:

insaneones@ubuntu:~ $ ghci    ___         ___ _   / _ \ /\  /\/ __(_)  / /_\// /_/ / /  | |      GHC Interactive, version 6.2.2, for Haskell 98. / /_\\/ __  / /___| |      http://www.haskell.org/ghc/ \____/\/ /_/\____/|_|      Type :? for help. Loading package base ... linking ... done. Prelude> let (x, y, z) = (5.0, 0.01, 0.02) Prelude> x + y + z == z + y + x False Prelude> :q Leaving GHCi. insaneones@ubuntu:~ $ hugs __   __ __  __  ____   ___      _________________________________________ ||   || ||  || ||  || ||__      Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__||  __||     Copyright (c) 1994-2003 ||---||         ___||           World Wide Web: http://haskell.org/hugs ||   ||                         Report bugs to: hugs-bugs@haskell.org ||   || Version: November 2003  _________________________________________ Haskell 98 mode: Restart with command line option -98 to enable extensions Type :? for help Prelude> let (x, y, z) = (5.0, 0.01, 0.02) in x + y + z == z + y + x False Prelude> :q [Leaving Hugs] insaneones@ubuntu:~ $

[rizzix]

ooh. guess not.. i just typed in the number (didn't use any variables) seemed to have printed out True. Wow, so unpredictable.. hmm

[wtd]

code:

$ ledit mit-scheme MIT/GNU Scheme running under GNU/Linux Type `^C' (control-C) followed by `H' to obtain information about interrupts. Copyright 2004 Massachusetts Institute of Technology. This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Image saved on Tuesday October 19, 2004 at 6:00:49 AM   Release 7.7.90 || Microcode 14.11 || Runtime 15.3 || SF 4.41 || LIAR 4.116   Edwin 3.114 1 ]=> (let ((x 5.0 )             (y 0.02)             (z 0.01))          (if (= (+ x y z) (+ y z x))             "foo"             "bar")) ;Value 11: "bar" 1 ]=>

[beard0]

Hooray for:

Mathematica:

x = 5.0; y = 0.02; z = 0.01; If[x + y + z == y + z + x, "True", "False"] (*This returns "True"!!!!*)

N.B. The absence of a ; on the last line is intentional. In mathematica, no end of line chacter is necessary, the semi-colon simply serves to supress output from the last statement. Had I placed a semi-colon on the end of the last line, I would have had no ouput.

[wtd]

O'Caml:

code:

# let x = 3.0 and y = 0.02 and z = 0.01 in    x +. y +. z = y +. x +. z;; - : bool = true

[wtd]

SML/NJ:

code:

- open Real; - let val x = 3.0 =     val y = 0.03 =     val z = 0.01 = in =     Real.==(x + y + z, y + x + z) = end; val it = true : bool

[xHoly-Divinity]

I think that multiplying by 100, rounding, then dividing by 100 is the fastest way to do it...

[MysticVegeta]

Did you check the date on the topic?

[xHoly-Divinity]

MysticVegeta wrote:

Did you check the date on the topic?

Why?

[beard0]

xHoly-Divinity wrote:

MysticVegeta wrote:

Did you check the date on the topic?

Why?

FFS, because you're necro-posting, bringing up old topics - this is not appreciated, and you have just done it again. If the topic is old, let it die. Read it if you're interested, and if you feel an overwelming urge to share some revelation that a certain post has brought to you, PM the poster, and leave the old topic be.