What is namespace ? Is it compulsory to use it ?

Question

i have just seen that every example which is given in this tutorial is using namespace before main function.

So i just wanna know that is it compulsory to use and what is the role of namespace.

Answer 1

it is recommended to use namespaces they similar to packages in java. Namespaces are for avoiding name collision of class name or variables name.. so that you can multiple varibale or class or method or functions with same name but within different namespaces..