following code segment into a file (named e.g. \c hello_lemon.cc)

 following code segment into a file (you can find it as \c

 to have a first working program that uses library LEMON.

 demo/hello_lemon.cc in the LEMON package) to have a first working

 program that uses library LEMON.

 \code

 \include hello_lemon.cc

 #include <iostream>

 #include <lemon/list_graph.h>

 int main()

 {

   typedef lemon::ListGraph Graph;

   typedef Graph::EdgeIt EdgeIt;

   typedef Graph::NodeIt NodeIt;

   using lemon::INVALID;

   Graph g;

   for (int i = 0; i < 3; i++)

     g.addNode();

   for (NodeIt i(g); i!=INVALID; ++i)

     for (NodeIt j(g); j!=INVALID; ++j)

       if (i != j) g.addEdge(i, j);

   std::cout << "Nodes:";

   for (NodeIt i(g); i!=INVALID; ++i)

     std::cout << " " << g.id(i);

   std::cout << std::endl;

   std::cout << "Edges:";

   for (EdgeIt i(g); i!=INVALID; ++i)

     std::cout << " (" << g.id(g.source(i)) << "," << g.id(g.target(i)) << ")";

   std::cout << std::endl;

 }

 \endcode

 If you have saved the preceding code into a file named, say, \c

 If your installation of LEMON into directory \c /usr/local was

 hello_lemon.cc and your installation of LEMON into directory \c

 successful then it is very easy to compile this program with the

 /usr/local was successful then it is very easy to compile this

 following command (the argument <tt>-lemon</tt> tells the compiler

 program with the following command (the argument <tt>-lemon</tt>

 that we are using the installed library LEMON):

 tells the compiler that we are using the installed library LEMON):