Data type conversion - Meeting 4

Now, we are going to learn on data type's conversion in PHP. Though in PHP we may undeclare the data-type, but we sometimes need to convert the data-type to get the exact results and avoid misleading results. Below is a script which show 3 kinds of how to convert a data-type in PHP. Please read carefully and uncomment one by one of each method of conversions to understand the functions.

<h3>Data type conversion</h3>
<hr><h4>Calculating A Circle</h4>
<?php
$rad = "10.5 cm";
define("phi",3.14);
//php has 3 ways on converting data types. to try it one by one you can uncomment each command below
/*settype($rad,"integer");*/ /*$rad = intval($rad);*/ /*$rad=(integer)$rad;*/
/*settype($rad,"double");*/ /*$rad = doubleval($rad);*/ /*$rad=(double)$rad;*/
/*settype($rad,"string);*/ /*$rad = strval($rad);*/ /*$rad=(string)$rad;*/
printf("Circle radius : %s <br>",$rad);
printf("Circle's area : %s cm²<br>",($rad*$rad*phi));
printf("Circle's circumference : %s cm<br>", (2*phi*$rad));
?>

The result should be like this:


as usual, any questions can be posted via comments and so do the answers. If needed iI will create a new label providing "questions and answers". See you next meeting.