How to print only 2 decimals after the point in float

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mhack

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Posted: 15th Oct 2003 17:37

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I'm ptining or using text to display my float numbers
And I need to display 2.00 instead of 2.000000009996?

Thank you,
Arseny

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Codger

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Posted: 15th Oct 2003 19:09

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it should be a# = int(a#*100)/100 but it does not work in DBP

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Van B

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Posted: 15th Oct 2003 19:18

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Hmmmm, try this instead:

a# = int(a#*100.00)/100.00

Might work, DB is fairly psychotic sometimes

. The .00 I added is to bring it to a real number, I reckon the 100 on it's own was forcing an integer.

Van-B

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Van B

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Posted: 15th Oct 2003 19:20

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Ohh, I made a function ages ago that gave a VB style format command, but with numerics only (e.g. a$=format(a#,"0.00"), I'll post it later tonight if I remember where it is.

Van-B

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Richard Davey

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Posted: 15th Oct 2003 19:21

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This does however:

a# = 652.009093490394039
print left$(str$(a#),len(str$(int(a#)))+3)

Change the +3 to however many decimal points you need to display. This version will work regardless of how many leading figures there are. If you know it will always be a value less than 10 then you can use the simpler:

print left$(str$(a#), 4)

Cheers,

Rich

"It's easy to be mean when death equals a high score screen."
"You can take your Quake and go away, I'd rather play Bubble Bobble any day."

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indi

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Posted: 15th Oct 2003 19:21

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this is one way if its intended for a direct output to the screen but hardly effective in a maths problem

+ Code Snippet

a# = 3.000045
a$ = STR$(a#)
a$ = left$(a$,4)
print a#
print a$

suspend for key
end

save ferris

http://www.lunarpixel.com/dt/

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Van B

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Posted: 15th Oct 2003 19:28

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I suppose it depends on how important rounding off is, a calculater would call 3.146 as 3.15 whereas text methods like those would call it as 3.14.

There's also the other problem of .5 - 3.50 would be returned as 3.5 in a maths method, but 3.5<space> in a text method.

Great, now I have a headache!

Van-B

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Codger

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Posted: 15th Oct 2003 19:35

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Here is a function that makes it tidy

a# = 652.109093490394039
FormatPrint(a#,2,20,20)

wait key

Function FormatPrint(a#,n,x,y)
Set Cursor x,y
Print left$(str$(a#),len(str$(int(a#)))+n+1)
EndFunction

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IanM

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Posted: 15th Oct 2003 20:05

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I posted this one for someone a week or so ago that pads the output if necessary

print FormatNumber(123.456,6,2)
print FormatNumber(123.456,8,2)
print FormatNumber(-123.456,8,2)
wait key

function FormatNumber(Number as float, TotalSize as integer, DecimalPlaces as integer)
   local FormattedDecimals as string
   local FormattedNumber as string

FormattedDecimals = str$( abs( Number - int(Number) ) )
   if len(FormattedDecimals) > 1
      FormattedDecimals=right$(FormattedDecimals, len(FormattedDecimals)-1)
   else
      FormattedDecimals="."
   endif
   while len(FormattedDecimals) <= DecimalPlaces
      FormattedDecimals = FormattedDecimals + "0"
   endwhile
   if len(FormattedDecimals) > DecimalPlaces+1 then FormattedDecimals = left$(FormattedDecimals, DecimalPlaces+1)

FormattedNumber = str$( int(Number) ) + FormattedDecimals

if len(FormattedNumber) < TotalSize
      FormattedNumber = space$( TotalSize - len(FormattedNumber) ) + FormattedNumber
   else
      if len(FormattedNumber) > TotalSize then FormattedNumber = right$(FormattedNumber, TotalSize)
   endif
endfunction FormattedNumber

+ Code Snippet

print FormatNumber(123.456,6,2)
print FormatNumber(123.456,8,2)
print FormatNumber(-123.456,8,2)
wait key



function FormatNumber(Number as float, TotalSize as integer, DecimalPlaces as integer)
   local FormattedDecimals as string
   local FormattedNumber as string

   FormattedDecimals = str$( abs( Number - int(Number) ) )
   if len(FormattedDecimals) > 1
      FormattedDecimals=right$(FormattedDecimals, len(FormattedDecimals)-1)
   else
      FormattedDecimals="."
   endif
   while len(FormattedDecimals) <= DecimalPlaces
      FormattedDecimals = FormattedDecimals + "0"
   endwhile
   if len(FormattedDecimals) > DecimalPlaces+1 then FormattedDecimals = left$(FormattedDecimals, DecimalPlaces+1)


   FormattedNumber = str$( int(Number) ) + FormattedDecimals

   if len(FormattedNumber) < TotalSize
      FormattedNumber = space$( TotalSize - len(FormattedNumber) ) + FormattedNumber
   else
      if len(FormattedNumber) > TotalSize then FormattedNumber = right$(FormattedNumber, TotalSize)
   endif
endfunction FormattedNumber

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mhack

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Posted: 15th Oct 2003 21:27

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Thank you guys for so many answers!
WOW!

I think I will go with simple one just for printing

Thank you,
Arseny

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Ian T

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Posted: 16th Oct 2003 01:39

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IanM-- thanks, I've been looking for something accurate like that for a while. Left$ worked until rounding off numbers became a big deal with the kind of detail I was working with. *shrugs*

--Mouse: Famous (Avatarless) Fighting Furball

A very nice %it, indeed.

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DarkBASIC Professional Discussion / How to print only 2 decimals after the point in float