# ConstructGraph

VTKExamples/Cxx/Graphs/ConstructGraph

### Description

This example shows how to construct a simple graph.

### Code

ConstructGraph.cxx

    #include <vtkSmartPointer.h>
    #include <vtkMutableUndirectedGraph.h>
    #include <vtkCircularLayoutStrategy.h>
    #include <vtkDataSetAttributes.h>
    #include <vtkDoubleArray.h>
    #include <vtkGraphLayoutView.h>
    #include <vtkIntArray.h>
    #include <vtkMutableUndirectedGraph.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkMutableUndirectedGraph> g =
        vtkSmartPointer<vtkMutableUndirectedGraph>::New();

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

      g->AddEdge ( v1, v2 );

      std::cout << "Number of vertices: "
                << g->GetNumberOfVertices() << std::endl;
      std::cout << "Number of edges: "
                << g->GetNumberOfEdges() << std::endl;

      g->AddEdge ( v1, v2 );

      std::cout << "Number of vertices: "
                << g->GetNumberOfVertices() << std::endl;
      std::cout << "Number of edges: "
                << g->GetNumberOfEdges() << std::endl;

      vtkSmartPointer<vtkGraphLayoutView> graphLayoutView =
        vtkSmartPointer<vtkGraphLayoutView>::New();
      graphLayoutView->AddRepresentationFromInput(g);
      graphLayoutView->ResetCamera();
      graphLayoutView->Render();
      graphLayoutView->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ConstructGraph)

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

    add_executable(ConstructGraph MACOSX_BUNDLE ConstructGraph.cxx )

    target_link_libraries(ConstructGraph ${VTK_LIBRARIES})

### Download and Build ConstructGraph

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

    cd ConstructGraph/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:

    ./ConstructGraph

WINDOWS USERS

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