add custom attribute option value programatically in Magento Cart Page.

–>first we have to create custom attribute with dropdown value in magento admin side.

–>get this dropdown option value in magento product view page in magento

–>now when user selected add to cart button this selected values going to your project root directory–>code–>core–>Mage–>checkout–>controllers–>cartController.php

–>now create magento session and stores magento custom¬† attribute values.