# ConstructTable

VTKExamples/Cxx/Utilities/ConstructTable

### Description

This example creates a 3x3 table. The columns MUST be added first - if you attempt to call AddRow type functions, they will not do anything (or produce errors) because the table still has 0 columns until you tell it otherwise. This example adds 3 empty columns to the table, then goes back and fills them in.

Warning: the table does not copy the data, so if you add the SAME column to the table each time, i.e. vtkSmartPointer col = vtkSmartPointer::New();

col->InsertNextValue(vtkVariant(0.0)); col->InsertNextValue(vtkVariant(0.0)); col->InsertNextValue(vtkVariant(0.0)); table->AddColumn(Col); table->AddColumn(Col); table->AddColumn(Col);

If you modify one of the entries in the table with Table->SetValue ( r,c, vtkVariant ( counter ) ); after they have all been set to the same column, the rth entry in EVERY column will be changed.

### Code

ConstructTable.cxx

    #include <vtkTable.h>
    #include <vtkVariant.h>
    #include <vtkVariantArray.h>
    #include <vtkSmartPointer.h>

    int main(int, char *[])
    {
      //construct an empty table
      vtkSmartPointer<vtkTable> table =
        vtkSmartPointer<vtkTable>::New();

      for ( unsigned int i = 0; i < 3; i++ )
      {
        vtkSmartPointer<vtkVariantArray> col =
          vtkSmartPointer<vtkVariantArray>::New();

        col->InsertNextValue ( vtkVariant ( 0.0 ) );
        col->InsertNextValue ( vtkVariant ( 0.0 ) );
        col->InsertNextValue ( vtkVariant ( 0.0 ) );
        table->AddColumn ( col );
      }

      //fill the table with values
      unsigned int counter = 0;
      for(vtkIdType r = 0; r < table->GetNumberOfRows(); r++ )
      {
        for(vtkIdType c = 0; c < table->GetNumberOfColumns(); c++ )
        {
          table->SetValue ( r,c, vtkVariant ( counter ) );
          counter++;
        }
      }

      //print information about the table
      std::cout << "NumRows: " << table->GetNumberOfRows() << std::endl;
      std::cout << "NumCols: " << table->GetNumberOfColumns() << std::endl;

      //display the table
      table->Dump ( 3 );

      //access elements of the table
      for(vtkIdType r = 0; r < table->GetNumberOfRows(); r++ )
      {
        for(vtkIdType c = 0; c < table->GetNumberOfColumns(); c++ )
        {
        vtkVariant v = table->GetValue( r,c);
        std::cout << "(r,c) = (" << r << "," << c << ") = " << v << std::endl;
        }
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ConstructTable)

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

    add_executable(ConstructTable MACOSX_BUNDLE ConstructTable.cxx )

    target_link_libraries(ConstructTable ${VTK_LIBRARIES})

### Download and Build ConstructTable

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

    cd ConstructTable/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:

    ./ConstructTable

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.