diff -r 030f1015f898 -r 01707a8a4ca6 demo/coloring.cc
--- a/demo/coloring.cc	Fri Jul 15 14:35:07 2005 +0000
+++ b/demo/coloring.cc	Fri Jul 15 16:01:55 2005 +0000
@@ -5,10 +5,26 @@
 #include <lemon/graph_reader.h>
 #include <lemon/graph_to_eps.h>
 
+#include <fstream>
+#include <iostream>
+
+
 using namespace std;
 using namespace lemon;
 
-int main() {
+int main(int argc, char *argv[]) 
+{
+  if(argc<2)
+  {
+      std::cerr << "USAGE: coloring <input_file.lgf>" << std::endl;
+      std::cerr << "The file 'input_file.lgf' has to contain a graph in LEMON format together with a nodemap called 'coords' to draw the graph (e.g. sample.lgf is not such a file)." << std::endl;
+      return 0;
+  }
+
+
+  //input stream to read the graph from
+  std::ifstream is(argv[1]);
+
   typedef UndirSmartGraph Graph;
   typedef Graph::Node Node;
   typedef Graph::NodeIt NodeIt;
@@ -17,7 +33,7 @@
 
   Graph graph;
 
-  UndirGraphReader<Graph> reader(std::cin, graph);
+  UndirGraphReader<Graph> reader(is, graph);
   Graph::NodeMap<xy<double> > coords(graph);
   reader.readNodeMap("coords", coords);