public void writeFeatures(PrintWriter fout) throws IOException {
// write the number of features
fout.println(Integer.toString(features.size()));
for (int i = 0; i < features.size(); i++) {
Feature f = (Feature) features.get(i);
fout.println(f.toString(data.cpInt2Str, data.lbInt2Str));
}
// wirte the line ###...
fout.println(Option.modelSeparator);
}
