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round off

Girish Solanke
Greenhorn

Joined: Mar 03, 2006
Posts: 13
Hi,

I want to round of integer to integer,
it means say i have one digit 46 then it should be rounded to 50,
& 44 should become 40.

same must be applicable to any no. of digit
Stan James
(instanceof Sidekick)
Ranch Hand

Joined: Jan 29, 2003
Posts: 8791
Old trick for ints from my COBOL days. To round to the nearest N add N-1, divide by N, multiply by N. To round up to nearest 10 ...

44 + 9 = 53
53 / 10 = 5
5 * 10 = 50

To round 45 up and 44 down, add N/2 instead of N

44 + 5 = 49
49 / 10 = 4
4 * 10 = 40

45 + 5 = 50
... -> 50


A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi
Girish Solanke
Greenhorn

Joined: Mar 03, 2006
Posts: 13
Hi Stan James,

You are right,

But in run time I may not know whether that digit is two digit or three or more than that ........
In that case How would i come know
&
Again I am expecting any inbuild function from java clases .......

Thanks for reply.....


Regards
marc weber
Sheriff

Joined: Aug 31, 2004
Posts: 11343

"Girish S,"

Please revise your display name to meet the JavaRanch Naming Policy. To maintain the friendly atmosphere here at the ranch, we like folks to use a first and a last name.

You can edit your name here. Thank you for your prompt attention!

-Marc


"We're kind of on the level of crossword puzzle writers... And no one ever goes to them and gives them an award." ~Joe Strummer
sscce.org
Tim McGuire
Ranch Hand

Joined: Apr 30, 2003
Posts: 820

I divide the number which I wish to round by 10:

46 / 10 = 4.6

Math.round(4.6) = 5

and restore it by multiplying by 10:
5 * 10 = 50.
Stan James
(instanceof Sidekick)
Ranch Hand

Joined: Jan 29, 2003
Posts: 8791
Girish, Tim's method or mine will work with numbers of any size to very near the max or min integer values. Try em and see!
 
Don't get me started about those stupid light bulbs.
 
subject: round off