How get output as integer?

Question

Input will consist of many number pairs, each on a separate line and the numbers are separated by a comma. The numbers can be as big as 100 digits long. The numbers will be integer and factional numbers and negative numbers will not be in input. Input will be terminated by end of file.

The output will be the reversed sums each on an individual line of its own. For each input pair, there should be one reversed sum.

I am writing this this code but not give correct result as integer value $number="36222813552166588601325554186418874001226412488844274840066661514,32814873748120642422248240335447 "; $int_array = array_map("intval", explode(",", $number));

$sum=0;
foreach($int_array as $item)
{
    $sum=$sum+strrev($item);        
}
$reverse_sum=str_replace("0","",strrev($sum));
echo $reverse_sum;

Got output: 91+E562719451714.1

Expected output: 68046696201386131133563894412955974001226412488844274840066661514

Answer 1

All numbers in PHP are limited to the system WORD size, i.e. 32 bits (PHP_INT_MAX = 2147483647) or 64 bits (PHP_INT_MAX = 9223372036854775807). Any numbers evaluated to be greater than this limit will be converted to a floating-point decimal.

Consider using BCMath, which stores numbers in the decimal (human-readable) form instead of in the binary form, as strings, so they can be virtually infinitely long:

$input = "36222813552166588601325554186418874001226412488844274840066661514,32814873748120642422248240335447";
$numbers = explode(",", $input);
$sum = "0";
foreach($numbers as $num){
    $sum = bcadd($sum, $num);
}

$reversed = str_replace("0", "", strrev($sum));
echo $reversed;

Output: 169699638879668496611618698146814555231688566125531822263

I have no idea how you would arrive at your expected output according to the code you provided. Nor do I understand why you strip out the zeroes. (Maybe you want to use ltrim(strrev($sum), "0") instead? The result would then be 16969960388079668490606100161860981468145552310688566125531822263, which is not what you would be looking for either.

If you have decimal numbers, consider adding the fourth parameter to your input.