is it imp to use using namespace plz reply

Answer 1

If you don't put "using namespace std;", you have to precise the namespace any time you use something from the standard library, like std::cout.

Answer 2

plz explain me briefly....

Answer 3

Without using namespace std; when you write for example cout <<; you'd have to put std::cout <<;

------------------------------------------------------------------------
#include <iostream>

int main()
{
std::cout << "Hello World";
system("pause");
return 0;

}
---------------------------------------------------------------------------
#include <iostream>

using namespace std;

int main()
{
cout << "Hello World";
system("pause");
return 0;

}