{"id":21283,"date":"2022-11-12T21:58:44","date_gmt":"2022-11-12T16:28:44","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-php-calculation-modulus-10-check-digit-generation-closed\/"},"modified":"2022-11-12T21:58:44","modified_gmt":"2022-11-12T16:28:44","slug":"solved-php-calculation-modulus-10-check-digit-generation-closed","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-php-calculation-modulus-10-check-digit-generation-closed\/","title":{"rendered":"[Solved] PHP Calculation – Modulus 10 check digit generation [closed]"},"content":{"rendered":"

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In case someone gets to the question wondering how to use modulus or ‘getting the rest of a division’ (%<\/code>):<\/p>\n

echo 5 % 3; \/\/ outputs 2\n<\/code><\/pre>\n<\/p>\n
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(You can take a look at a step-by-step output after this first part)<\/em><\/p>\n
This is the commented function:<\/p>\n
function func_name($docnum){\n\n    \/\/ make sure there is just numbers in $docnum\n    $docnum = preg_replace(\"\/[^0-9]\/\",\"\",$docnum);      \n\n    \/\/ change order of values to use in foreach\n    $vals = array_reverse(str_split($docnum));\n\n    \/\/ multiply every other value by 2\n    $mult = true;\n    foreach($vals as $k => $v){\n        $vals[$k] = $mult ? $v*2: $v;\n        $vals[$k] = (string)($vals[$k]);\n        $mult = !$mult;\n    }\n\n    \/\/ checks for two digits (>9)\n    $mp = array_map(function($v){\n        return ($v > 9) ? $v[0] + $v[1] : $v;\n    }, $vals);\n\n    \/\/ adds the values\n    $sum = array_sum($mp);\n\n    \/\/gets the mod\n    $md = $sum % 10;\n\n    \/\/ checks how much for 10\n    $result = 10 - $md;\n\n    \/\/ returns the value\n    return $result;\n}\n<\/code><\/pre>\n
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Some test runs:<\/p>\n
$docnum = 5843;\necho func_name($docnum);\n<\/code><\/pre>\n
Output:<\/p>\n
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8<\/p>\n<\/blockquote>\n
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$docnum = 1111;\necho func_name($docnum);\n<\/code><\/pre>\n
Output:<\/p>\n
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4<\/p>\n<\/blockquote>\n
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$docnum = '-5a84fadsafds.fdar3';\necho func_name($docnum);\n<\/code><\/pre>\n
Output:<\/p>\n
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8<\/p>\n<\/blockquote>\n
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$docnum = 4321;\necho func_name($docnum);\n<\/code><\/pre>\n
Output:<\/p>\n
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6<\/p>\n<\/blockquote>\n
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This codes outputs the steps…<\/p>\n
$docnum = '-5a84fadsafds.fdar3';\n\necho 'Original Value: ';\nprint_r($docnum);\necho '<hr>';\n\n$docnum = preg_replace(\"\/[^0-9]\/\",\"\",$docnum); \n\necho 'Numbers only: ';\nprint_r($docnum);\necho '<hr>';\n\n$vals = array_reverse(str_split($docnum));\n\necho 'Reversed Value: ';\nprint_r($vals);\necho '<hr>';\n\n$mult = true;\nforeach($vals as $k => $v){\n    $vals[$k] = $mult ? $v*2: $v;\n    $vals[$k] = (string)($vals[$k]);\n    $mult = !$mult;\n}\n\necho 'After mult.: ';\nprint_r($vals);\necho '<hr>';\n\n$mp = array_map(function($v){\n    return ($v > 9) ? $v[0] + $v[1] : $v;\n}, $vals);\n\necho 'Checked for >9: ';\nprint_r($mp);\necho '<hr>';\n\n$sum = array_sum($mp);\n\necho 'All values together: ';\nprint_r($sum);\necho '<hr>';\n\n$md = $sum % 10;\n\necho 'Mod: ';\nprint_r($md);\necho '<hr>';\n\n$result = 10 - $md;\n\necho 'Final result: ';\nprint_r($result);\necho '<hr>';\n<\/code><\/pre>\n
Output:<\/p>\n
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Original Value: -5a84fadsafds.fdar3 
\n  Numbers only: 5843 
\n  Reversed Value: Array ( [0] => 3 [1] => 4 [2] => 8 [3] => 5 )  
\n  After mult.: Array ( [0] => 6 [1] => 4 [2] => 16 [3] => 5 )  
\n  Checked for >9: Array ( [0] => 6 [1] => 4 [2] => 7 [3] => 5 )  
\n  All values together: 22 
\n  Mod: 2 
\n  Final result: 8 <\/p>\n<\/blockquote>\n
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Read more about things used in the code:<\/p>\n