How to Round Floating point number (Double) to 2 Decimal Points in J2ME JavaME

August 24th, 2007 Posted in J2ME / JavaME, Tips, Tricks, Guide, newbie

The minimalistic design of JavaME CLDC means that a lot of packages from the standard Java has to be trimmed out and this includes the flexible NumberFormat packages which is useful for formatting numbers in Java.

The absence of NumberFormat and java.text package means that you can't even round a floating point number!

However there is a workaround to this problem, with this simple method, you can round floating point number (Double) roughly to a specific number of decimal points.

PLAIN TEXT
JAVA:
  1. //round to 2 decimal points
  2. double number = (double)(int)((bmi+0.005)*100.0)/100.0;
  3.  
  4. //round to 4 decimal points
  5. double number = (double)(int)((bmi+0.00005)*10000.0)/10000.0;

The code above shows you how to round a double to 2 and 4 decimal points, you can change the number of zeros above to round it to your desired decimal points.

Hope that will help you in your JavaME / J2ME programming.

[tags]j2me,javame,midp,java,sdk,j2se[/tags]

 

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This entry was posted on Friday, August 24th, 2007 at 2:49 pm and is filed under J2ME / JavaME, Tips, Tricks, Guide, newbie. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

8 Responses to “How to Round Floating point number (Double) to 2 Decimal Points in J2ME JavaME”

  1. thanasis Says:

    October 17th, 2007 at 8:44 pm

    thnx



  2. taro Says:

    January 6th, 2008 at 4:15 pm

    thanks lots!



  3. pao Says:

    June 14th, 2008 at 7:54 am

    excelent!!!, very very ingenious. You are a genious!! very thanks



  4. ana Says:

    July 23rd, 2008 at 2:52 am

    thank u very much!



  5. viv Says:

    September 2nd, 2008 at 1:45 am

    Thanx man



  6. Eric Says:

    October 11th, 2008 at 8:32 am

    Thanks



  7. Sameer Nafdey Says:

    March 19th, 2009 at 1:46 pm

    Awesome! Its a very small snippet but very useful. You saved my hell lot of time. Thanks man. You rocks.



  8. Léo Says:

    May 19th, 2009 at 1:06 am

    This is not rounding, is trunking.
    22.92893723062 turns into 22.9288 and not 22.9289
    47.026586582836 turns 47.0265 and not 47.0266



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