An implementation of the C++ standard library is provided as a part of
GCC. The following program uses the standard library string
class to reimplement the Hello World program:
#include <string> #include <iostream> using namespace std; int main () { string s1 = "Hello,"; string s2 = "World!"; cout << s1 + " " + s2 << '\n'; return 0; }
The program can be compiled and run using the same commands as above:
$ g++ -Wall hellostr.cc $ ./a.out Hello, World!
Note that in accordance with the C++ standard, the header files for the
C++ library itself do not use a file extension. The classes in the
library are also defined in the std
namespace, so the directive
using namespace std
is needed to access them, unless the prefix
std::
is used throughout (as in the previous section).