Why we need user defined function to use in c++ ???

Question

what is the need of user defined ? Why should we use it ?

Answer 1

it's not obligatory to use user defined functions in c++ or any programming languages for that matter. but if you need something special and it doesn't already exist you have to make it yourself.

Answer 2

if you want create something new user defined functions are use ful for you. it's just like you are buying a pizza instead of making it your self. sometime making a pizza at home good than buying it because you can make as you want. most of times using library functions help you to save your time and reduce the length of your code.