using namespace in program block : namespace « Language Basics « C++ Tutorial






#include <iostream.h>

namespace first
{
  int var = 5;
}

namespace second
{
  double var = 3.1416;
}

int main () {
  {
    using namespace first;
    cout << var << endl;
  }
  {
    using namespace second;
    cout << var << endl;
  }
  return 0;
}
5
3.1416








1.9.namespace
1.9.1.A namespace
1.9.2.Use a namespace
1.9.3.A nested namespace
1.9.4.Reuse namespace
1.9.5.Reference variables in namespaces
1.9.6.using namespace in program block
1.9.7.Reference global variable, variable in the nested namespace
1.9.8.Use Namespace to organize functions
1.9.9.function in a namespace reference variables in the same namespace
1.9.10.using namespace std;
1.9.11.Use function defined in a namespace
1.9.12.Using unnamed namespaces.
1.9.13.Using namespace aliases
1.9.14.Using the using directive