diff options
| -rw-r--r-- | lib/pure/math.nim | 25 | ||||
| -rw-r--r-- | web/news.txt | 2 |
2 files changed, 27 insertions, 0 deletions
diff --git a/lib/pure/math.nim b/lib/pure/math.nim index bd6764433..1edbfcab6 100644 --- a/lib/pure/math.nim +++ b/lib/pure/math.nim @@ -312,6 +312,23 @@ else: exponent = round(ex) result = x / pow(2.0, ex) +proc splitDecimal*[T: float32|float64](x: T): tuple[intpart: T, floatpart: T] = + ## Breaks `x` into an integral and a fractional part. + ## + ## Returns a tuple containing intpart and floatpart representing + ## the integer part and the fractional part respectively. + ## + ## Both parts have the same sign as `x`. Analogous to the `modf` + ## function in C. + var + absolute: T + absolute = abs(x) + result.intpart = floor(absolute) + result.floatpart = absolute - result.intpart + if x < 0: + result.intpart = -result.intpart + result.floatpart = -result.floatpart + {.pop.} proc degToRad*[T: float32|float64](d: T): T {.inline.} = @@ -399,3 +416,11 @@ when isMainModule: doAssert floatIsEqual(round(-547.652, -2), -500.0) doAssert floatIsEqual(round(-547.652, -3), -1000.0) doAssert floatIsEqual(round(-547.652, -4), 0.0) + + block: # splitDecimal() tests + doAssert floatIsEqual(splitDecimal(54.674).intpart, 54.0) + doAssert floatIsEqual(splitDecimal(54.674).floatpart, 0.674) + doAssert floatIsEqual(splitDecimal(-693.4356).intpart, -693.0) + doAssert floatIsEqual(splitDecimal(-693.4356).floatpart, -0.4356) + doAssert floatIsEqual(splitDecimal(0.0).intpart, 0.0) + doAssert floatIsEqual(splitDecimal(0.0).floatpart, 0.0) diff --git a/web/news.txt b/web/news.txt index 3dd6c4e1e..3290baa5c 100644 --- a/web/news.txt +++ b/web/news.txt @@ -61,6 +61,8 @@ Library Additions - Added ``strscans`` module that implements a ``scanf`` for easy input extraction. - Added a version of ``parseutils.parseUntil`` that can deal with a string ``until`` token. The other versions are for ``char`` and ``set[char]``. +- Added ``splitDecimal`` to ``math.nim`` to split a floating point value + into an integer part and a floating part (in the range -1<x<1). Compiler Additions |