Jaguar Calculator has trouble with addition?

shatfield1529

shatfield1529

s|hatfield not shat|field
I was using Jaguar's calculator to figure out how much of a grocery bill I owed, and I got some freaky results from the 'paper tape' drawer; see below:

9/28/02
5:16:58 PM
------------
1.66 +
1.66 +
1.66 +
1.66 +
3.49 +
1.5 +
1.5 +
1.99 +
4.99 +
1.99 +
3.99 +
4.99 +
2.29 +
3.29 +
2.5 +
2.99 +
2.99 +
8.99 +
8.99 +
8.99 +
8.99 +
3.99 +
3.99 +
3.99 =
93.06999999999998 ◊
Click to expand...

Has anyone else experienced this?
 
I got the same thing when I did your list... that is strange. I'm assuming there's a very simple, logical explanation that we're missing here... perhaps the mode of the calculator or something simple like that...
 
Originally posted by ElDiabloConCaca
I got the same thing when I did your list... that is strange. I'm assuming there's a very simple, logical explanation that we're missing here... perhaps the mode of the calculator or something simple like that...
Click to expand...
There is no mystery here. This seems to be nothing more than trying to add a sequence of decimal numbers that exceed the limits of the calculator's decimal to binary conversion routine. You get the same sort of thing in a BASIC program.
 
You're right, it's almost certainly the decimal to binary conversion routine. But it's still a bug that should have been caught.

I tried to add up the numbers in the windows calc and I got 91.41. It looks like I entered the numbers incorrectly but I can't tell because it doesn't have a paper tape.

I guess I'm not happy with either one. :(

Vanguard
 
The paper trail says the same as in the original post, but the "display window" says 93.07. Weird, I can understand that there is a bug in the binary conversion, but not that it is evident in only one of two windows in the same application.
 
Originally posted by elander
The paper trail says the same as in the original post, but the "display window" says 93.07. Weird, I can understand that there is a bug in the binary conversion, but not that it is evident in only one of two windows in the same application.
Click to expand...
My version of Jaguar gives the same result on the "paper tape" as the display window.
 
Originally posted by vanguard


I tried to add up the numbers in the windows calc and I got 91.41.
Click to expand...

You left out one of the 1.66's, and made one of them 1.36.

PS. Luckily I never use the calc, so it doesn't matter. Of course I do have it in my login items so that if ever one of my friends wants to use it, it will pop to the front very fast. Sometimes you have to simulate the speed.

dave17lax
 
LOL. I didn't even notice we _had_ a calc program. As computer geeky as I am (I'll be the first to have a cranial implant, I'm sure), I insist on having a real calculator on my desk.

-Rob
 
Note the smiley with the tongue sticking out, like so :p . That usually denotes a post which is not meant to be taken seriously (in other words, the post was meant in jest).

Another example: Anyone know a website where one could get an original sig? :p

:D
 
For kicks, I tried it out on the calculator in X.1.5 and I got 93.07.

I think I've run into this before with some FileMaker calculations. If you're interested in that discussion, click here.
 
Your problem is that you used a decimal point! Goofy people don't realize that computers use binary points ;)

In all honesty write 1/3 as a decimal oops you can't because it decimal representation is not terminating. So at some point you stop writing threes and say that it is good enough for government work and move on. The computer is doing the same thing except it doesn't think in base 10 decimal but in base 2. The problem is that the numbers you are adding up do not have finite representations base 2. If they did everything woudl be O.K. since they don't some fudging occures.

As an illustration think of the problem of adding up 1/3's in decimal. If I use a base 3 representation it is easy 1/3 = 0.1 so 0.1 + 0.1 + 0.1 = 1 Neat Huh!

The answer you need is to count pennies and not dollars. This is what bakns do because of this very problem. Shift you decimals two digits over do the math and then check your result.

-Eric

P.S. Oh do I know I glossed of some stuff, if anyone cares I can fill in the cracks. This was just getting long and it is late.
 
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