Rounding float numbers to 2 decimal places

Rounding float numbers to 2 decimal places - Printable Version

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Rounding float numbers to 2 decimal places - rbiondi - 2023-12-29

Hello,

I need to round or at least truncate a Float variable to 2 decimal places.
Do you know how this could be accomplished since there's no ROUND function?

Thank you very much,
Rogerio

RE: Rounding float numbers to 2 decimal places - boriel - 2023-12-30

There is a trick for that which can be accomplished in several ways. Here's an example of a ROUND function (explained in the ZX Spectrum Manual):

Code:
FUNCTION Round(n as Float, decimals as UByte = 0) AS Float
  DIM tmp as Float
  DIM d10 = 10^decimals
  IF n >= 0 THEN
    LET tmp = INT(n * d10 + 0.5)
  ELSE
    LET tmp = INT(n * d10 - 0.5)
  END IF
  RETURN tmp / d10
END FUNCTION

This function will round towards +/- infinity.
Use with Round(number, digits)

I'll include it in the math library.

RE: Rounding float numbers to 2 decimal places - rbiondi - 2023-12-31

Thank you very much!

A sugestion would be adding an optional parameter to str$ function:

Code:
dim floatnum as Float = 0.135[/font][/size][/color]
print str$(floatnum, 2)

>> prints 0.13