Fibonacci Series

0 1 1 2 3 5 8 13 21 34  
Here, 0 + 1 = 1  
            1 + 1 = 2  
            3 + 2 = 5  

<?php  
$num = 0;  
$n1 = 0;  
$n2 = 1;  
echo "<h3>Fibonacci series for first 12 numbers: </h3>";  
echo "\n";  
echo $n1.' '.$n2.' ';  
while ($num < 10 )  
{  
    $n3 = $n2 + $n1;  
    echo $n3.' ';  
    $n1 = $n2;  
    $n2 = $n3;  
    $num = $num + 1;  
?>  

<?php  
/* Print fiboancci series upto 12 elements. */  
$num = 12;  
echo "<h3>Fibonacci series using recursive function:</h3>";  
echo "\n";  
/* Recursive function for fibonacci series. */  
function series($num){  
    if($num == 0){  
    return 0;  
    }else if( $num == 1){  
return 1;  
}  else {  
return (series($num-1) + series($num-2));  
}   
}  
/* Call Function. */  
for ($i = 0; $i < $num; $i++){  
echo series($i);  
echo "\n";  
}