c++

Question

what is the use of:
using namespace std; ??

which we didn't use in dev or turbo c++ and the program run well.

Answer 1

[https://www.sololearn.com/Discuss/238855/what-is-namespace-in-cpp]
[https://www.sololearn.com/Discuss/231066/what-is-the-actual-meaning-of-using-namespace-std-in-c-and-why-we-are-using-it]
[https://www.sololearn.com/Discuss/199494/please-tell-me-the-use-of-using-namespace]
[https://www.sololearn.com/Discuss/165872/namespace-std]
[https://www.sololearn.com/Discuss/1206/why-do-we-have-to-write-using-namespace-std-every-time]
[https://www.sololearn.com/Discuss/12872/why-do-we-use-using-namespace-std-is-it-necessary-or-is-there-an-alternative]
[https://www.sololearn.com/Discuss/9557/please-explain-the-use-of-using-the-statement-using-namespace-std]

Answer 2

This is the namespace which qualify the function which you want to call. Simply sad you can avoid the function collission if they have the same name. If some package/module contain the same function name you can qualify from which function you want to call (from which package/module).Withou the namespace you need to full qualify the function name.For example insted of mystd.display("someone") you can use only display in the code if you use using namespace mystd. Your module mynamespace needs to be marked as namespace mystd.

Answer 3

not for all compilar it run succesful beacouse in it app code going to internet and auto-compiler debug some mistakes