Why is std namespace required here?

Question

#include <iostream>
using namespace std;

int main() {
    cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
    return 0;
}

If I delete the 2nd statement, the assembly will fail.

Why is this necessary?

Answer 1

Since coutthey endlare contained inside the namespace std.

You can delete the line using namespace stdand put std::coutand instead std::endl.

Here is an example that should make namespaces clear:

Stuff.h:

namespace Peanuts
{
  struct Nut
  {
  };
}


namespace Hardware
{
  struct Nut
  {
  };
}

- using namespace Hardware, Nut . , , : 1) 2) using.

, .

, #include:

#include <iostream> cout endl. , std, iostream.

Answer 2

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Answer 3

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