how do you tell if a number is even or odd

title says it all

you can use division…….

in java, i know you can do this

var Num = 4

if (Num % 2 === Num/2)
{
Number is even
}
else
{
Number is odd
}

its java though (tinn57, syntax?)

i know java im asuming mod symbol works in lua

Bam!

Read on!

Here's a simple function for you:

function GetType(Number)
local Derp = Number % 2
if Derp == 0 then
return "Even"
else
return "Odd"
end
end

Another nice way is to use bitwise operators, every even number has a zero last bit. To check this:

function getType(number)
if bit.band(number,1) == 0 then
  return "Even"
end
return "Odd"
end

Although im not sure how much of a difference this makes in lua.

Either way works. It is up to him what he wants to use. I would rather use the bitwise operator.

It's much easier, way faster, and native to lua to use the modulo operator.

function isEven(num)
  return num % 2 == 0
end

I guess that works as well :P/> Still a fan of the bitwise operator

Im still new to lua, so as i said i wasn't sure if the bitwise operator had an advantage over the modulo operator. I know that in some languages it definitely does.

In this case, the modulo operator has the bitwise operator beaten. I still like it though ^_^/>

modulo = java :P/>

Java = nil :wacko:/>

SuicidalSTDz, on 25 March 2013 - 02:29 PM said:

Java = nil :wacko:/>/>

Java = null :P/>

Engineer, on 25 March 2013 - 02:31 PM said:

SuicidalSTDz, on 25 March 2013 - 02:29 PM said:

Java = nil :wacko:/>/>

Java = null :P/>

Lua perspective dear Watson ^_^/>

If Java had true Garbage Collection, well, there would be no Java..

there is also a modulo function in the math library…
its math.fmod iirc. because math.modf gets the fraction part of the number.

SuicidalSTDz, on 25 March 2013 - 02:57 PM said:

Engineer, on 25 March 2013 - 02:31 PM said:

Java = null :P/>

Lua perspective dear Watson ^_^/>

Nope, u gunna talk about Java, you look at it from a Java perspective.

TheOriginalBIT, on 25 March 2013 - 03:09 PM said:

Nope, u gunna talk about Java, you look at it from a Java perspective.

But, but, no! Unacceptable!

TheOriginalBIT, on 25 March 2013 - 03:09 PM said:

because math.modf gets the fraction part of the number.

Wait. Why does modf even exist? It's ridiculously easy to make modf yourself.

function modf(n)
  return n - n%1, n%1
end

Kingdaro, on 25 March 2013 - 03:15 PM said:

Wait. Why does modf even exist? It's ridiculously easy to make modf yourself.

Why do most functions exist… for convenience to the developer not to have to make the function each time… most of the math and string functions can be easily made…

TheOriginalBIT, on 25 March 2013 - 03:21 PM said:

Why do most functions exist… for convenience to the developer not to have to make the function each time… most of the math and string functions can be easily made…

Yet people still complain to Cloudy and Dan: "This is too hard, make it easier!"

SuicidalSTDz, on 25 March 2013 - 03:25 PM said:

TheOriginalBIT, on 25 March 2013 - 03:21 PM said:

Why do most functions exist… for convenience to the developer not to have to make the function each time… most of the math and string functions can be easily made…

Yet people still complain to Cloudy and Dan: "This is too hard, make it easier!"

I was talking about in programming in general…. why does any api exist. to make our life as developers easier. we CAN programme without these APIs, but they are there so we don't have to write all these functionalities.

TheOriginalBIT, on 25 March 2013 - 03:26 PM said:

SuicidalSTDz, on 25 March 2013 - 03:25 PM said:

TheOriginalBIT, on 25 March 2013 - 03:21 PM said:

Why do most functions exist… for convenience to the developer not to have to make the function each time… most of the math and string functions can be easily made…

Yet people still complain to Cloudy and Dan: "This is too hard, make it easier!"

I was talking about in programming in general…. why does any api exist. to make our life as developers easier. we CAN programme without these APIs, but they are there so we don't have to write all these functionalities.

I was just reminiscing on how people here can't make simple functions by themselves, such as a goto function, and well, you know what I mean..

SuicidalSTDz, on 25 March 2013 - 03:30 PM said:

I was just reminiscing on how people here can't make simple functions by themselves, such as a goto function, and well, you know what I mean..

goto isn't a function. its a statement/instruction. and it should never be used. when used a velociraptor will appear and bite off your head. (well according to my uni Lecturer anyways) :P/>

TheOriginalBIT, on 25 March 2013 - 03:21 PM said:

Why do most functions exist… for convenience to the developer not to have to make the function each time… most of the math and string functions can be easily made…

It was my impression that it was Lua's goal to be lightweight and only provide what was needed, which was the reason for not having a round() function implemented (that rounds to any factor, e.g. round(38, 5) –> 40) as I've read on lua-users.

The math library is just ridiculously huge and some of it's functions shouldn't even be there in my opinion, like "pow", "fmod" and "modf" as you've mentioned.

Though I suppose there would be some use to having some of these, if you can't use operators (or simple logic) for some reason.

String functions though, I'd basically just quit Lua altogether if even one of them weren't implemented. In fact, the patterns system is even lacking in some aspects.

TheOriginalBIT, on 25 March 2013 - 03:33 PM said:

when used a velociraptor will appear and bite off your head. (well according to my uni Lecturer anyways) :P/>

Ok, now that is a bit extreme! I was referring to a goto function for turtles btw… I would never want a goto function for anything other than that :P/>

Kingdaro, on 25 March 2013 - 03:36 PM said:

Though I suppose there would be some use to having some of these, if you can't use operators (or simple logic) for some reason.

Well the % operator would go a little something like this in the number data type impl

number.__mod = math.fmod

or if you prefer expanded and pointless

number.__mod = function( a,b ) return math.fmod( a,b ) end

Kingdaro, on 25 March 2013 - 03:36 PM said:

String functions though, I'd basically just quit Lua altogether if even one of them weren't implemented. In fact, the patterns system is even lacking in some aspects.

I didn't like the lack of the functions, hence me implementing the Extended String Library

SuicidalSTDz, on 25 March 2013 - 03:38 PM said:

Ok, now that is a bit extreme! I was referring to a goto function for turtles btw… I would never want a goto function for anything other than that :P/>/>/>

A goto would be nice. It would make it easy to break out of multiple loops, or to skip iterations in a loop.:

while blah do
  while otherblah do
    while blahblahblah do
      if fun then
        goto gtfo
      elseif nofun then
        goto omfg
      end
    end
  end
  ::gtfo::
end
::omfg::

You could also emulate python's "else" for while loops, without using a boolean.

local people = {'insert','a','list','of','names'}

for i=1, #people do
  if people[i] == 'Buzz Killington' then
    print 'Everyone left the party.'
    goto left
  end
end
print 'The party has started.'
::left::

Kingdaro, on 25 March 2013 - 03:49 PM said:

while blah do
  while otherblah do
	while blahblahblah do
	  if fun then
		goto gtfo
	  elseif nofun then
		goto omfg
	  end
	end
  end
  ::gtfo::
end
::omfg::

Umm.. nice example?

mind = blown