php - Storing and retrieving $_SESSION variables -

i've got problem. i'm sure i'm being stupid can't seem able rertive $_session variable. run throught code variable called $setup post each time reset. each time run through code increment $setup starts off no value has value 1 , then value 2. when it's one, set session posted value. next time when it's two, session doesn't seem have value.

this code when page loaded:

<?php     session_start();     $setup=$_post['reset'];     if ($setup==null)     {         $setup=0;     }     elseif ($setup==1)     {         $_session['value1']=$_post['value1'];         $value1=$_session['value1'];     }     elseif ($setup==2)     {         $value1=$_session['value1'];         $_session['value2']=$_post['value2'];         $value2=$_session['value2'];     } ?> 

when setup 1 can print out value1 when setup 2 use code

echo $value2 . " " . $value1 . "."; 

all value2 followed dot. doing wrong here?

in part of code :

elseif ($setup==2) {     $value1=$_session['value1'];//here     $_session['value2']=$_post['value2'];     $value2=$_session['value2']; } 

$_session['value1'] empty $value1 empty , instead of suggest code:

elseif ($setup==2) {     if(isset($_session['value1'])   $value1=$_session['value1'];     else $value1='some value test';      $value2=$_session['value2']; } 

also:

 echo $value2 . " " . $value1 "."; 

should :

 echo $value2 . " " . $value1 . ".";//if want dot in end  

or :

echo $value2 . " " . $value1 ;//without dot int end of line