& Quot; The Bible & quot; The recursion problem is confusing for 555 of the day. This post was last edited by iamsai from 2013-09-2421: 00: 08. & lt ;? Php $ strhello; reverse_ I ($ str); function & nbsp; reverse_ I ($ str) {if (strlen ($ str "Bible") the recursion problem cannot be solved 555 a day...
This post was last edited by iamsai at 21:00:08
$str='hello';
reverse_i($str);
function reverse_i($str)
{
if(strlen($str)>0)
{
reverse_i(substr($str,1));
}
echo substr($str,0,1);
return;
}
?>
Please refer to my questions:
The output result of this program is the inverted olleh output.
After reverse_ I (substr ($ str, 1) in the loop body; hello ello llo lo o
Echo substr ($ str, 0, 1); output o.
What value does the return statement return? Is it returned to the fourth row? What is the subsequent execution order? Who can help me analyze? Thank you!
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------ Solution --------------------
If (strlen ($ str)> 0)
?? {???
???? Reverse_ I (substr ($ str, 1); // This is a recursive call.
<--- Return here
??}
?? Echo? Substr ($ str, 0, 1 );
?? Return;
