<?php
// https://stackoverflow.com/a/1343685/5305370
function isqrt($n)
{
$b = 0;
while($n >= 0)
{
$n = $n - $b;
$b = $b + 1;
$n = $n - $b;
}
return $b - 1;
}
$a = 9;
$b = isqrt($a);
echo "a = ".$a.", sqrt(a) = b = ".$b."\n";
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