Why do we need to do usingnamespace std and what is int main and why we use it?

Question

Well my question is the title please,please answer Im a 12 year old trying to learn C++

Example to help you:

#include <iostream>
using namespace std;

int main()
{
cout << "Hello world!";
return 0;
}

Answer 1

using namespace std prevents from having to do std:: in front of thing like cin, cout, endl, etc. int main is the, as it says, main function of your program. This is where everything starts.

Answer 2

std is the standard namespace of c++. If hadn't put it there you had to write for example std::cout for printing. std is the namespace of the standard c++ library. You can use other namespace and define your own - but that is only important for large projects. You will be fine in std for a while. int main ist the main function of a c/c++ program. If you want to have runnable code - you will need this function. it's int - because main returns an integer - it's standard to return 0, if your program runs fell or return with some failure value if something had gone wrong.

Answer 3

My Advice

Just forget about it and keep moving forward ...when you start module on classes and object you will be able to use #include and namespace