Floor implementation

Question

Target: Write a floor() function from scratch.

Manipulating like converting float to string, and cutting all after dot are allowed.

All languages are allowed.

Any usage of built in language functions (like toInteger()) or similar is not allowed, casting operators are not allowed.

So, your task is implement floor() function without using casting and built in language functions.

Your function must support at least max 32-bit integer values (you will never receive negative values).

Forced casting (like somevar as float) and normal casting - such as(int) somevar - is not allowed, any built in functions, not allowed, all other stuff allowed.

Winner: Shortest implemention.

Answer 1

C (gcc), 57 bytes

i;int f(float n){for(i=-2147483648;i<=n;i++);return i-1;}

Try it online! (it takes too long, so I changed it to start from 0.

Answer 2

CJam, 6 bytes

q'.%0=

Try it online!

I found several 6 bytes solution but I can't do less than this.

Answer 3

Javascript, 6 chars

x=>~~x

Test:

f = x=>~~x

document.addEventListener('input', event => {
  var x = event.target.valueAsNumber
  document.querySelector('output').textContent = x + " => " + f(x)
})

<input type=number> <output></output>

Answer 4

Python 2, 21 13 bytes

lambda x:x//1

Outputs a float if input is float, outputs an integer if input is integer.

Try it online!

Answer 5

Japt, 2 bytes

|0

Try it online

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Alternative

ÂU

Try it online

Answer 6

Batch, 53 bytes

@for /f "tokens=1 delims=." %%a in ("%1")do @echo %%a

Trims everything after .