list2101.cpp

teach yourself C++ in 21 days 第五版

#define DemoVersion
#define SW_VERSION 5
#include <iostream>
 
using std::endl;
using std::cout;

int main()
{
   cout << "Checking on the definitions of DemoVersion,";
   cout << "SW_VERSION, and WINDOWS_VERSION..." << endl;

   #ifdef DemoVersion
      cout << "DemoVersion defined." << endl;
   #else
      cout << "DemoVersion not defined." << endl;
   #endif

   #ifndef SW_VERSION
      cout << "SW_VERSION not defined!" << endl;
   #else
      cout << "SW_VERSION defined as: "
                << SW_VERSION << endl;
   #endif

   #ifdef WINDOWS_VERSION
      cout << "WINDOWS_VERSION defined!" << endl;
   #else
      cout << "WINDOWS_VERSION was not defined." << endl;
   #endif

   cout << "Done."  << endl;
   return 0;
}