How to take values associated with radio buttons & Check box in PHP

There is a big confusion in some freshers that how to take  values associated with radio button as well as check box in PHP. Here is the piece of code that helps to do so.

cricket <input type='radio' name='radio' id='radio1' value='cricket' />
football <input type='radio' name='radio' id='radio2' value='football' />
tennis <input type='radio' name='radio' id='radio3' value='tennis' />

Don't forget to add values attribute in input tag

Now lets look how to take values in php

<?php
    $val = $_POST['radio'];
    echo $val;
?>

this code will print the opted input radio.

similarly for check box

cricket <input type='checkbox' name='check[]' id='check1' value='cricket' />
football <input type='checkbox' name='check[]' id='check2' value='football' />
tennis <input type='checkbox' name='check[]' id='check3' value='tennis' />

here also we can have above piece of code. But if you choose cricket and football you will get it as an array
 so you can have

$var = implode(",",$_POST['check']);
echo $var

this will print cricket,football