what is functional requirement

Answer 1

functional = mandatory to have in the program to achieve all primary goals (eg. obtain a certain level of security ) it really depends on the system requirements.
non-functional = extra components that can be added once all the functional requirements can be met. ( eg. obtain location and store lat/lng, calculate speed....)

Answer 2

Hi Sorous,
let me clear your doubt with simple English.. Requirement is nothing but gathering useful information where as functional is all about how it is working.. Hence 'functional requirement' is gathering information on to how a piece of software/application should work..