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# UniformRandomNumber

VTKEx/Cxx/SimpleOperations/UniformRandomNumber

### Description

This example generates 3 random numbers between 0 and 2 from a uniform distribution.

Other languages

See (CSharp)

Question

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### Code

UniformRandomNumber.cxx

    #include <vtkMath.h>
    #include <time.h>

    int main(int, char *[])
    {
      // Set the number of random numbers we wish to produce to 3.
      unsigned int numRand = 3;

      // Without this line, the random numbers will be the same every iteration.
      vtkMath::RandomSeed(time(NULL));

      // Generate numRand random numbers from a uniform distribution between 0.0 and 2.0
      for(unsigned int i = 0; i < numRand; i++)
      {
        double a = vtkMath::Random(0.0,2.0);
        std::cout << a << std::endl;
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(UniformRandomNumber)

    find_package(VTK COMPONENTS
      vtkvtkCommonCore QUIET)
    if (NOT VTK_FOUND)
      message("Skipping UniformRandomNumber: ${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(UniformRandomNumber MACOSX_BUNDLE UniformRandomNumber.cxx )
      target_link_libraries(UniformRandomNumber PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(UniformRandomNumber MACOSX_BUNDLE UniformRandomNumber.cxx )
      target_link_libraries(UniformRandomNumber PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS UniformRandomNumber
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build UniformRandomNumber

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

    cd UniformRandomNumber/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:

    ./UniformRandomNumber

WINDOWS USERS

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