# VectorArrayUnknownLength

VTKExamples/Cxx/Utilities/VectorArrayUnknownLength

### Description

This example creates a VTK style float array of vectors. This can be easily interchanged with vtkIntArray, vtkDoubleArray, etc.

The only difference between this example and the VectorArrayKnownLength example is that `SetNumberOfValues()` is not called, and `SetTuple()` is replaced by `InsertNextTuple()`.

### Code

VectorArrayUnknownLength.cxx

    #include <vtkSmartPointer.h>
    #include <vtkFloatArray.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkFloatArray> distances =
        vtkSmartPointer<vtkFloatArray>::New();
      distances->SetName("Distances");
      distances->SetNumberOfComponents(3);

      //set values
      for(vtkIdType i = 0; i < 5; i++)
      {
        float tuple[3];
        tuple[0] = (float)i + 0.1;
        tuple[1] = (float)i + 0.2;
        tuple[2] = (float)i + 0.3;
        //this will allocate memory as necessary
        distances->InsertNextTuple(tuple);
      }

      //get values
      for(vtkIdType i = 0; i < distances->GetNumberOfTuples(); i++)
      {
        double d[3];
        distances->GetTuple(i, d);
        std::cout << d[0] << " " << d[1] << " " << d[2] << std::endl;
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(VectorArrayUnknownLength)

    find_package(VTK COMPONENTS
      vtkCommonCore QUIET)
    if (NOT VTK_FOUND)
      message("Skipping VectorArrayUnknownLength: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(VectorArrayUnknownLength MACOSX_BUNDLE VectorArrayUnknownLength.cxx )
      target_link_libraries(VectorArrayUnknownLength PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(VectorArrayUnknownLength MACOSX_BUNDLE VectorArrayUnknownLength.cxx )
      target_link_libraries(VectorArrayUnknownLength PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS VectorArrayUnknownLength
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build VectorArrayUnknownLength

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

    cd VectorArrayUnknownLength/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:

    ./VectorArrayUnknownLength

WINDOWS USERS

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