proofoftom · January 19, 2018 22:25
diff --git a/CarryOperations.php b/CarryOperations.php
 <?php
 /**
 * @file Math helper to find the number of carry operations in an addition operation.
 */

 class CarryOperations
 {
    /**
     * Counts the number of carry operations when adding two numbers.
     *
     * @param integer $num1 First number to be added.
     * @param integer $num2 Second number to be added.
     *
     * @return integer Number of carry operations.
     */
    public static function count($num1, $num2)
    {
        // Split the two numbers into columns.
        $num1_columns = str_split($num1);
        $num2_columns = str_split($num2);
        // Set initial amount of carries.
        $carries = 0;
        // By default there is no previous carry.
        $carried = false;

        // Since the order is indeterminate, find the number with the most columns.
        $amount_of_columns = (strlen($num1) > strlen($num2)) ? strlen($num1) : strlen($num2);

        // Loop through each column and determine if the respective column carries.
        for ($i = $amount_of_columns; $i > 0 ; $i--) {
            $column_sum = array_pop($num1_columns) + array_pop($num2_columns);
            // If this column carries, save the carry to apply to the next column.
            $carried = _isCarry($column_sum, $carried);
            if ($carried) $carries++; 
        }

        return $carries;
    }

    /**
     * Calculate if an added column incures a carry.
     *
     * @param integer $column_sum The sum of the two columns.
     * @param boolean $carried    True (1) if the previous column carried.
     *
     * @return boolean True if this column incures a carry.
     */
    private function _isCarry($column_sum, $carried)
    {
        if ($column_sum + $carried >= 10) {
            return true;
        } else {
            return false;
        }
    }
 }

 echo CarryOperations::count(1, 9999);

 // Output: 4
	<?php
	/**
	* @file Math helper to find the number of carry operations in an addition operation.
	*/

	class CarryOperations
	{
	/**
	* Counts the number of carry operations when adding two numbers.
	*
	* @param integer $num1 First number to be added.
	* @param integer $num2 Second number to be added.
	*
	* @return integer Number of carry operations.
	*/
	public static function count($num1, $num2)
	{
	// Split the two numbers into columns.
	$num1_columns = str_split($num1);
	$num2_columns = str_split($num2);
	// Set initial amount of carries.
	$carries = 0;
	// By default there is no previous carry.
	$carried = false;

	// Since the order is indeterminate, find the number with the most columns.
	$amount_of_columns = (strlen($num1) > strlen($num2)) ? strlen($num1) : strlen($num2);

	// Loop through each column and determine if the respective column carries.
	for ($i = $amount_of_columns; $i > 0 ; $i--) {
	$column_sum = array_pop($num1_columns) + array_pop($num2_columns);
	// If this column carries, save the carry to apply to the next column.
	$carried = _isCarry($column_sum, $carried);
	if ($carried) $carries++;
	}

	return $carries;
	}

	/**
	* Calculate if an added column incures a carry.
	*
	* @param integer $column_sum The sum of the two columns.
	* @param boolean $carried True (1) if the previous column carried.
	*
	* @return boolean True if this column incures a carry.
	*/
	private function _isCarry($column_sum, $carried)
	{
	if ($column_sum + $carried >= 10) {
	return true;
	} else {
	return false;
	}
	}
	}

	echo CarryOperations::count(1, 9999);

	// Output: 4