//namesp.cpp -- demo namespace, by tsaiwn@csie.nctu.edu.tw
#include <stdio.h>
#include <iostream>
//Note that ALL C++ library are in namespace std
// using namespace std;  // 若不寫則所有C++程式庫的都要寫成 std::

namespace Taiwan {
   void haha( ) { printf("haha haha 哈!\n"); }
}
namespace japan {
   void haha( ) { printf("Dou Dou Yo Lou Si Ku!\n"); }
   void bye( ) { printf("Sa Yo Na La!\n"); }
}
namespace USA {
   void haha( ) { printf("won won How do you do!\n"); }
   void bye( ) { printf("Bye! See U!\n"); }
}
namespace Taiwan {   //注意這也是在 Taiwan
   void bye( ) { printf("Good bye! 再見!!\n"); }
}

void bye(int x) { printf("BBB BBB BBBBB!\n"); } //name overloading

using namespace Taiwan;
//using namespace USA;
//using namespace japan;
int main( ) {
   // cout << "Welcome ..." << endl; // 若有 using namespace std;
   std::cout << "Welcome ..." << std::endl;
   printf("Now do    japan::haha( );\n");
   japan::haha( );
   printf("\n");
   printf("Now do    USA::haha( );\n");
   USA::haha( );
   printf("Now do    USA::bye( );\n");
   USA::bye( );
   printf("=== now do haha( ); bye( );\n");
   haha( );
   bye( );
   printf("Note the using namespace ...\n");
   ::bye(38);   // this function is in default namespace
   return 0;
}
/******
D:\COURSE\OOP\ppnt>g++ namesp.cpp

D:\COURSE\OOP\ppnt>a
Welcome ...
Now do    japan::haha( );
Dou Dou Yo Lou Si Ku!

Now do    USA::haha( );
won won How do you do!
Now do    USA::bye( );
Bye! See U!
=== now do haha( ); bye( );
haha haha 哈!
Good bye! 再見!!
Note the using namespace ...
BBB BBB BBBBB!

D:\COURSE\OOP\ppnt>
********************************/