Namespace,,,, Why to use?

#1

what is the actual work of namespace int eh program, why we have to establish it, or if we dont we have to mention std:: before every keywords, in TURBO C4 why it doesnot require namespace

#2

hello @akb.tech17
refer this answer-> https://www.quora.com/What-does-using-namespace-std-mean-in-C++