How to find Length of string without using function?

$count = 0;
for ($i = 0; $i < 1000000; $i++) {
     if(isset($temp[$i]))  
        $count++;
     else
         break;
}
print_r($count);

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Another simplified version

$count = 0;
for ($i = 0; TRUE; $i++) {
     if(isset($temp[$i]))
        $count++;
     else
         break;
}
print_r($count);