# TreeBFSIterator

VTKExamples/Cxx/Graphs/TreeBFSIterator

### Code

TreeBFSIterator.cxx

    #include <vtkSmartPointer.h>
    #include <vtkMutableDirectedGraph.h>
    #include <vtkTree.h>
    #include <vtkTreeBFSIterator.h>

    int main(int argc, char *argv[])
    {
      //create a tree
      vtkSmartPointer<vtkMutableDirectedGraph> g =
        vtkSmartPointer<vtkMutableDirectedGraph>::New();

      vtkIdType v1 = g->AddVertex();
      vtkIdType v2 = g->AddVertex();
      vtkIdType v3 = g->AddVertex();

      g->AddEdge(v1, v2);
      g->AddEdge(v1, v3);

      vtkSmartPointer<vtkTree> tree =
        vtkSmartPointer<vtkTree>::New();
      tree->CheckedShallowCopy(g);

      //setup the iterator
      vtkIdType root = 0;

      vtkSmartPointer<vtkTreeBFSIterator> bfsIterator =
          vtkSmartPointer<vtkTreeBFSIterator>::New();
      bfsIterator->SetStartVertex(root);
      bfsIterator->SetTree(tree);

      //traverse the tree in a breadth first fashion
      while(bfsIterator->HasNext())
      {
        vtkIdType nextVertex = bfsIterator->Next();
        std::cout << "Next vertex: " << nextVertex << std::endl;
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(TreeBFSIterator)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(TreeBFSIterator MACOSX_BUNDLE TreeBFSIterator.cxx)

    target_link_libraries(TreeBFSIterator ${VTK_LIBRARIES})

### Download and Build TreeBFSIterator

Danger

The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.

Click here to download TreeBFSIterator and its CMakeLists.txt file. Once the tarball TreeBFSIterator.tar has been downloaded and extracted,

    cd TreeBFSIterator/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./TreeBFSIterator

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.