PHP Program for Ceiling in a sorted array

<?php
// Function to get index of 
// ceiling of x in arr[low..high] 
function ceilSearch($arr, $low, $high, $x)
{

    // If x is smaller than or equal 
    // to first element, then return 
    // the first element 
    if($x <= $arr[$low])
        return $low; 
    
    // Otherwise, linearly search
    // for ceil value 
    for($i = $low; $i < $high; $i++)
    {
        if($arr[$i] == $x)
            return $i;
    
        // if x lies between arr[i] and 
        // arr[i+1] including arr[i+1], 
        // then return arr[i+1] 
        if($arr[$i] < $x && 
           $arr[$i + 1] >= $x)
            return $i + 1;
    }     
    
    // If we reach here then x is greater 
    // than the last element of the array,
    // return -1 in this case 
    return -1;
}

// Driver Code
$arr = array(1, 2, 8, 10, 10, 12, 19);
$n = sizeof($arr);
$x = 3;
$index = ceilSearch($arr, 0, $n - 1, $x);
if($index == -1)
    echo("Ceiling of " . $x . 
         " doesn't exist in array ");
else
    echo("ceiling of " . $x . " is " . 
                        $arr[$index]);

// This code is contributed by Ajit.
?>

<?php
// PHP Program for Ceiling in 
// a sorted array

// Function to get index of ceiling
// of x in arr[low..high]
function ceilSearch($arr, $low, 
                    $high, $x)
{
    $mid; 
    
    /* If x is smaller than or 
       equal to the first element,
       then return the first element */
    if($x <= $arr[$low])
        return $low; 
    
    /* If x is greater than the
       last element, then return
       -1 */
    if($x > $arr[$high])
        return -1; 
    
    /* get the index of middle
       element of arr[low..high] */
    // low + (high - low)/2
    $mid = ($low + $high)/2; 
    
    /* If x is same as middle element,
       then return mid */
    if($arr[$mid] == $x)
        return $mid;
        
    /* If x is greater than arr[mid],
       then either arr[mid + 1]    is 
       ceiling of x or ceiling lies 
       in arr[mid+1...high] */
    else if($arr[$mid] < $x)
    {
        if($mid + 1 <= $high && 
           $x <= $arr[$mid + 1])
            return $mid + 1;
        else
            return ceilSearch($arr, $mid + 1, 
                              $high, $x);
    }
    
    /* If x is smaller than arr[mid],
       then either arr[mid] is ceiling
       of x or ceiling lies in 
       arr[low....mid-1] */
    else
    {
        if($mid - 1 >= $low && 
           $x > $arr[$mid - 1])
            return $mid;
        else
         return ceilSearch($arr, $low, 
                           $mid - 1, $x);
    }
}

// Driver Code
$arr = array(1, 2, 8, 10, 10, 12, 19);
$n = sizeof($arr);
$x = 20;
$index = ceilSearch($arr, 0, $n - 1, $x);
if($index == -1)
    echo("Ceiling of $x doesn't exist in array ");
else
    echo("ceiling of $x is"); 
    echo(isset($arr[$index]));

// This code is contributed by nitin mittal.
?>