# [erlang-questions] casting float to integer

Per Hedeland per@REDACTED
Sat May 12 14:22:49 CEST 2007

```Robert Virding <robert.virding@REDACTED> wrote:
>
>
>floor(V) when V >= 0 -> trunc(V);
>floor(V) -> - trunc(-V) - 1.

No, try floor(-1.0).

--Per

>Robert
>
>Per Hedeland wrote:
>> Håkan Stenholm <hokan.stenholm@REDACTED> wrote:
>>> Nitin Verma wrote:
>>>> Hi All,
>>>>
>>>> I am looking for a function/BIF that can help me.
>>>>
>>>> Problem: I need a float number's floored integer. That is if:
>>>> A = f(5/2), then A = 2 and
>>>> A = f(1000/501), then A = 1
>>>>
>>>> I found 'round/1' but it just rounds-off .
>>
>>> see erlang.erl documentation:
>>>
>>> -----------------------------------------------------------------------
>>>
>>> *|trunc(Number) -> int()|*
>>
>> But trunc is not the same as floor - though maybe Nitin actually wants
>> trunc, or even div (which "truncates" the same way as trunc), as
>> indicated by the examples. When I actually needed floor/1, I came up
>> with this somewhat bizarre-looking definition:
>>
>> floor(V) when V >= 0 -> trunc(V);
>> floor(V) -> trunc(V - trunc(V) + 1) + trunc(V) - 1.
>>
>> There may be a better way to do it...
>>
>> --Per Hedeland

```