Let us first answer the question <b>"What do I want to use LEMON for?"

 </b>. 

 LEMON is a C++ library, so you can use it if you want to write C++ 

 programs. What kind of tasks does the library LEMON help to solve? 

 It helps to write programs that solve optimization problems that arise

 frequently when <b>designing and testing certain networks</b>, for example

 in telecommunication, computer networks, and other areas that I cannot

 think of now. A very natural way of modelling these networks is by means

 of a <b> graph</b> (we will always mean a directed graph by that). 

 So if you want to write a program that works with 

 graphs then you might find it useful to use our library LEMON.

 Some examples are the following:

 - First we give two examples that show how to instantiate a graph. The

 first one shows the methods that add nodes and edges, but one will

 usually use the second way which reads a graph from a stream (file).

 -# The following code fragment shows how to fill a graph with data.

  \code

   typedef ListGraph Graph;

   typedef Graph::Edge Edge;

   typedef Graph::InEdgeIt InEdgeIt;

   typedef Graph::OutEdgeIt OutEdgeIt;

   typedef Graph::EdgeIt EdgeIt;

   typedef Graph::Node Node;

   typedef Graph::NodeIt NodeIt;

   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);

  \endcode 

  -#

 - If you want to solve some transportation problems in a network then 

 you will want to find shortest paths between nodes of a graph. This is 

 usually solved using Dijkstra's algorithm. A utility

 that solves this is  the \ref lemon::Dijkstra "LEMON Dijkstra class".

 A simple program using the \ref lemon::Dijkstra "LEMON Dijkstra class" is

 as follows (we assume that the graph is already given in the memory):

 \code

 \endcode

 - If you want to design a network and want to minimize the total length

 of wires then you might be looking for a <b>minimum spanning tree</b> in

 an undirected graph. This can be found using the Kruskal algorithm: the 

 class \ref lemon::Kruskal "LEMON Kruskal class" does this job for you.

 The following code fragment shows an example:

 \code

 \endcode

 Some more detailed introduction can be obtained by following the links 

 below: