How do i Check a post ID is odd or even?

[Neo_Angelo]

Ok i'm pretty new to the whole coding business and i'm trying to figure out what i'm doing wrong, basically what i'd like to do is create a check for the post ID that determines whether the post ID is odd or even and output two different things depending on the outcome, for example i want the Post layout to have the postbit information on the left if the post ID is odd and the postbit info on the right if its even.

Heres what i mean:

If post ID = even

User info | Post

If post = odd

Post | Userinfo

heres the code i've been working on so far and i do appologise for the exceedingly appalling use of code, can someone walk me through what i've done wrong and explain to me how i should go about it? i'd really appreciate it as i want to learn. I've been using W3 schools as a reference.

// Function to determine odd or even
function is_odd( $int )
{
  return( $int & 1 );
}


<vb:if( is_odd($postid) )>

  <div class="postdetails">
		<div class="userinfo">
			<div class="username_container">
			<vb:if condition="$post['userid']">
				{vb:raw memberaction_dropdown}
				{vb:raw post.onlinestatus}
			<vb:else />
				<span class="username guest">{vb:raw post.musername}</span>
			</vb:if>
			</div>
			<span class="usertitle">
				{vb:raw post.usertitle}
			</span>
			<vb:if condition="$post['rank']">
				<span class="rank">{vb:raw post.rank}</span>
			</vb:if>
			{vb:raw template_hook.postbit_userinfo_left}
			<vb:if condition="$show['reputation']">
				<span class="postbit_reputation" id="repdisplay_{vb:raw post.postid}_{vb:raw post.userid}" title="{vb:raw post.username} {vb:raw post.level}">
					<vb:each from="reputationdisplay" value="row">
						<img class="{vb:raw row.class}" src="{vb:stylevar imgdir_reputation}/reputation_{vb:raw row.posneg}{vb:raw row.imgext}" alt="" />{vb:raw row.rowend}
					</vb:each>
				</span>
			</vb:if>
			<vb:if condition="$show['avatar']">
			<a class="postuseravatar" href="{vb:link member, {vb:raw post}}" title="{vb:rawphrase {vb:raw post['onlinestatusphrase']}, {vb:raw post.username}}">
				<img src="{vb:raw post.avatarurl}" alt="{vb:rawphrase xs_avatar, {vb:raw post.username}}" title="{vb:rawphrase xs_avatar, {vb:raw post.username}}" />
			</a>
			</vb:if> 
			<vb:if condition="$post['userid']">
				<hr />
				<dl class="userinfo_extra">
					<vb:if condition="$post['joindate']"><dt>{vb:rawphrase join_date}</dt> <dd>{vb:raw post.joindate}</dd></vb:if>
					<vb:if condition="$post['field2']"><dt>{vb:rawphrase location_perm}</dt> <dd>{vb:raw post.field2}</dd></vb:if>
					<vb:if condition="$post['age']"><dt>{vb:rawphrase age}</dt> <dd>{vb:raw post.age}</dd></vb:if>
					<dt>{vb:rawphrase posts}</dt> <dd>{vb:raw post.posts}</dd>	
					{vb:raw template_hook.postbit_userinfo_right_after_posts}
				</dl>
				<vb:if condition="$show['infraction'] OR $show['reppower']">
				<dl class="user_rep">
					<vb:if condition="$show['infraction']">
					<dt>{vb:rawphrase infractions}</dt> 
					<dd>{vb:raw post.warnings}/{vb:raw post.infractions} ({vb:raw post.ipoints})</dd>
					</vb:if>
					<vb:if condition="$show['reputation']">
						<vb:if condition="$show['reppower']">
					<dt>{vb:rawphrase reppower}</dt> 
					<dd id="reppower_{vb:raw post.postid}_{vb:raw post.userid}">{vb:raw post.reppower}</dd> 
						</vb:if>
					</vb:if>
				</dl>
				</vb:if>
				{vb:raw template_hook.postbit_userinfo_right}
				<div class="imlinks">
					{vb:raw post.icqicon} {vb:raw post.aimicon} {vb:raw post.msnicon} {vb:raw post.yahooicon} {vb:raw post.skypeicon}
				</div>
			</vb:if>
		</div>

<vb:else />

<div align="right">
		<div class="userinfo">
			<div class="username_container">
			<vb:if condition="$post['userid']">
				{vb:raw memberaction_dropdown}
				{vb:raw post.onlinestatus}
			<vb:else />
				<span class="username guest">{vb:raw post.musername}</span>
			</vb:if>
			</div>
			<span class="usertitle">
				{vb:raw post.usertitle}
			</span>
			<vb:if condition="$post['rank']">
				<span class="rank">{vb:raw post.rank}</span>
			</vb:if>
			{vb:raw template_hook.postbit_userinfo_left}
			<vb:if condition="$show['reputation']">
				<span class="postbit_reputation" id="repdisplay_{vb:raw post.postid}_{vb:raw post.userid}" title="{vb:raw post.username} {vb:raw post.level}">
					<vb:each from="reputationdisplay" value="row">
						<img class="{vb:raw row.class}" src="{vb:stylevar imgdir_reputation}/reputation_{vb:raw row.posneg}{vb:raw row.imgext}" alt="" />{vb:raw row.rowend}
					</vb:each>
				</span>
			</vb:if>
			<vb:if condition="$show['avatar']">
			<a class="postuseravatar" href="{vb:link member, {vb:raw post}}" title="{vb:rawphrase {vb:raw post['onlinestatusphrase']}, {vb:raw post.username}}">
				<img src="{vb:raw post.avatarurl}" alt="{vb:rawphrase xs_avatar, {vb:raw post.username}}" title="{vb:rawphrase xs_avatar, {vb:raw post.username}}" />
			</a>
			</vb:if> 
			<vb:if condition="$post['userid']">
				<hr />
				<dl class="userinfo_extra">
					<vb:if condition="$post['joindate']"><dt>{vb:rawphrase join_date}</dt> <dd>{vb:raw post.joindate}</dd></vb:if>
					<vb:if condition="$post['field2']"><dt>{vb:rawphrase location_perm}</dt> <dd>{vb:raw post.field2}</dd></vb:if>
					<vb:if condition="$post['age']"><dt>{vb:rawphrase age}</dt> <dd>{vb:raw post.age}</dd></vb:if>
					<dt>{vb:rawphrase posts}</dt> <dd>{vb:raw post.posts}</dd>	
					{vb:raw template_hook.postbit_userinfo_right_after_posts}
				</dl>
				<vb:if condition="$show['infraction'] OR $show['reppower']">
				<dl class="user_rep">
					<vb:if condition="$show['infraction']">
					<dt>{vb:rawphrase infractions}</dt> 
					<dd>{vb:raw post.warnings}/{vb:raw post.infractions} ({vb:raw post.ipoints})</dd>
					</vb:if>
					<vb:if condition="$show['reputation']">
						<vb:if condition="$show['reppower']">
					<dt>{vb:rawphrase reppower}</dt> 
					<dd id="reppower_{vb:raw post.postid}_{vb:raw post.userid}">{vb:raw post.reppower}</dd> 
						</vb:if>
					</vb:if>
				</dl>
				</vb:if>
				{vb:raw template_hook.postbit_userinfo_right}
				<div class="imlinks">
					{vb:raw post.icqicon} {vb:raw post.aimicon} {vb:raw post.msnicon} {vb:raw post.yahooicon} {vb:raw post.skypeicon}
				</div>
			</vb:if>
		</div>

</vb:if>