[SOLVED] Please help with Mathematical Validation

[rvdb86]

Hi, i am trying to perform a mathematical check on a number and was hoping some one could help me out! let me explain the situation.

 

the user enters a 9 digit number - i have form validation that ensures its a number and 9 digits long

i then need to x the first number by 1, the 2nd number by 2, the 3rd number by 1, the 4th number by 2 etc...

 

the sum of the previous step should be exactly devisible by 11

 

Example:

Number: 1 2 3 4 5 6 7 8 9

multiply: 1 2 1 2 1 2 1 2 1

result1:  1 4 3 8 5 1 7 1 9 !! -- if the result should return only 1 digit, if the result is => 10 result = 1

result2:  1+4+3+8+5+1+7+1+9 = 39

finally i need to check that the sum of result2 (39) is exactly devisible by 11

 

if any one know of a function that could help me, or tell me how i can count through the int to multiply by 1 or 2 and how to check if a number is exactly devisible by 11 i would very much appreciate it.

 

thank you in advance to anyone who takes the time to look at this!

[peuge]

First off explode the number into an array

$nums = explode($number);

 

Then you loop through the array and check if each number is divisible by two, and if it is multiply by two.

$result = 0;

for ($i=0;$i <=9; $i++){
  if ($nums[$i]  % $divideby == 0){
    $nums[$i] = $nums * 2;
  }
  
  if ($nums[$i] >=10){
    $nums[$i] = 1;
  }
  
  $result = $result + $nums[$i];
}

 

Havent tested it but you get the idea

[rvdb86]

ok thanks for the suggestion im going to try it out now

[rvdb86]

the explode() function is returning an error that it is not being used in the correct way.

I looked into the explode() function on php.net and the instructions there show that there need to be a delimiter between the numbers.

 

how can i break the 9 digit number into an array without having delimiters?

[andy_b42]

<?php
$userInput = "123456789"; // make the input a string if it is not already

function checkDivisibleByEleven($userInput){
	$sum = 0;
	for($count = 0; $count < 9; $count++){
		$currentVal = $userInput[$count];
		if($count%2 == 1){
			$toAdd = $currentVal * 2;
			if($toAdd > 9){$toAdd = 1;}
			$sum += $toAdd;
			//echo "ODD current val = " . $currentVal . " to add = " . $toAdd . " sum = " . $sum . "<br/>";
		}else{
			$toAdd = $currentVal * 1;
			if($toAdd > 9){$toAdd = 1;}
			$sum += $toAdd;
			//echo "EVEN current val = " . $currentVal . " to add = " . $toAdd . " sum = " . $sum . "<br/>";
		}
	}

	if($sum%11 == 0){
		echo $userInput . ": Sum's to " . $sum . ": is divisible by 11";
	}else{
		echo $userInput . ": Sum's to " . $sum . ": is <b>NOT</b> divisible by 11";
	}
}

checkDivisibleByEleven($userInput);
?>

 

I think that should do it all, i havent fully tested it, buy i think its ok

[Mark Baker]

how can i break the 9 digit number into an array without having delimiters?

Usr str_split() rather than explode()

[rvdb86]

thank you so much to everyone who has helped me out!

 

Where would i edit the script that anndy_b42 so kindly posted so that if the number being multiplied by either 1 or 2 >= 10 it would add these to gether. for example:

7*2 = 14 so the result i want is 1+4 = 5

 

 

[rvdb86]

i think it is this part of the code i need to change:

 

            if($toAdd > 9){$toAdd = 1;}
            $sum += $toAdd;

 

i just don't know how to add the two numbers together

would i use str_split() on the result and then do something like $toAdd[1] + $toAdd[2]

or am i on the wrong track?

[sasa]

<?php
function chek_sum($num){
$sum = 0;
$mult = 1;
$num = str_split(trim($num));
if (count($num) != 9) return false;
foreach ($num as $n) {
	$n *= $mult;
	$mult = 3 - $mult;
	$sum += (int) ($n/10) + $n % 10; 
}
return $sum % 11 == 0;
}

$number = '123456786';
if(chek_sum($number)) echo 'OK'; else echo 'no';
?>

[andy_b42]

thank you so much to everyone who has helped me out!

 

Where would i edit the script that anndy_b42 so kindly posted so that if the number being multiplied by either 1 or 2 >= 10 it would add these to gether. for example:

7*2 = 14 so the result i want is 1+4 = 5

 

 

I think this will do it

<?php
$userInput = "123456789"; // make the input a string if it is not already

function checkDivisibleByEleven($userInput){
	$sum = 0;
	for($count = 0; $count < 9; $count++){
		$currentVal = $userInput[$count];
		if($count%2 == 1){
			$toAdd = $currentVal * 2;
			if($toAdd > 9){
				$toAddString = $toAdd;
				$i = 0;
				while($toAddString[$i] != ""){
					$toAdd += $toAddString[$i];
					$i++;
				}
			}
			$sum += $toAdd;
			//echo "ODD current val = " . $currentVal . " to add = " . $toAdd . " sum = " . $sum . "<br/>";
		}else{
			$toAdd = $currentVal * 1;
			if($toAdd > 9){
				$toAddString = $toAdd;
				$i = 0;
				while($toAddString[$i] != ""){
					$toAdd += $toAddString[$i];
					$i++;
				}
			}
			$sum += $toAdd;
			//echo "EVEN current val = " . $currentVal . " to add = " . $toAdd . " sum = " . $sum . "<br/>";
		}
	}

	if($sum%11 == 0){
		echo $userInput . ": Sum's to " . $sum . ": is divisible by 11";
	}else{
		echo $userInput . ": Sum's to " . $sum . ": is <b>NOT</b> divisible by 11";
	}
}

checkDivisibleByEleven($userInput);
?>

[rvdb86]

guys thank you so much! please know that i appreciate the time you took to help me, and hopefully with my new knowledge who knows maybe i will be able to help someone like you guys helped me out!

 

great forum, and great people!

[Mark Baker]

Can be simplified further:

$userInput = "123456789"; // make the input a string if it is not already

function checkDivisibleByEleven($userInput) {
$sum = 0;
for($count = 0; $count < 9; $count++) {
	$currentVal = $userInput{$count};
	if ($count%2 == 1) {
		$sum += array_sum(str_split($currentVal * 2));
	} else {
		$sum += $currentVal;
	}
}

if (($sum % 11) == 0) {
	echo $userInput . ": Sums to " . $sum . ": is divisible by 11";
} else {
	echo $userInput . ": Sums to " . $sum . ": is <b>NOT</b> divisible by 11";
}
}

checkDivisibleByEleven($userInput);

[rvdb86]

hey guys, i know i marked this topic as solved, but maybe some one could help me solve the following:

 

the code above is for a known amount of numbers (9). How would change the code for an unknown amount of numbers between 11-19 and the 1,2,1,2 numbering has to start from right to left. Example:

 

13 numbers: 1 2 3 4 5 6 7 8 9 0 1 2 3

                1 2 1 2 1 2 1 2 1 2 1 2 1

 

12 numbers: 1 2 3 4 5 6 7 8 9 0 1 2

                2 1 2 1 2 1 2 1 2 1 2 1

 

 

[andy_b42]

<?php

$userInput = "123456789"; // make the input a string if it is not already

 

function checkDivisibleByEleven($userInput, $leftToRight){ // $leftToRight is a boolean variable

$sum = 0;

$count = 0;

 

if($leftToRight){

$oddMultiplier = 1;

$evenMultipler = 2;

}else{

$oddMultiplier = 2;

$evenMultipler = 1;

}

 

while($userInput[$count] != ""){

$currentVal = $userInput[$count];

if($count%2 == 1){

$toAdd = $currentVal * $evenMultiplier;

if($toAdd > 9){

$toAddString = $toAdd;

$i = 0;

while($toAddString[$i] != ""){

$toAdd += $toAddString[$i];

$i++;

}

}

$sum += $toAdd;

echo "ODD current val = " . $currentVal . " to add = " . $toAdd . " sum = " . $sum . "<br/>";

}else{

$toAdd = $currentVal * $oddMultiplier;

if($toAdd > 9){

$toAddString = $toAdd;

$i = 0;

while($toAddString[$i] != ""){

$toAdd += $toAddString[$i];

$i++;

}

}

$sum += $toAdd;

echo "EVEN current val = " . $currentVal . " to add = " . $toAdd . " sum = " . $sum . "<br/>";

}

$count++;

}

 

if($sum%11 == 0){

echo $userInput . ": Sum's to " . $sum . ": is divisible by 11";

}else{

echo $userInput . ": Sum's to " . $sum . ": is <b>NOT</b> divisible by 11";

}

}

 

checkDivisibleByEleven($userInput, true);

checkDivisibleByEleven($userInput, false);

?>

[Mark Baker]

$userInput = "1234567890123456789"; // make the input a string if it is not already

function checkDivisibleByEleven($userInput) {
$sum = 0;
$userInput = strrev($userInput);
$strLength = strlen($userInput);
for($count = 0; $count < $strLength; $count++) {
	$currentVal = $userInput{$count};
	if ($count%2 == 1) {
		$sum += array_sum(str_split($currentVal * 2));
	} else {
		$sum += $currentVal;
	}
}

if (($sum % 11) == 0) {
	echo $userInput . ": Sums to " . $sum . ": is divisible by 11";
} else {
	echo $userInput . ": Sums to " . $sum . ": is <b>NOT</b> divisible by 11";
}
}

checkDivisibleByEleven($userInput);

[rvdb86]

hey andy_b42, thanks for your help but it didnt seem to work

no worries Mark Bakers script worked 100% thanks soo much!

 

u guys are life savers!