    # CStruct Examples
    require 'cstruct'

    # struct Point in Ruby:
    class Point < CStruct
      int32:x
      int32:y
    end

    # struct PointF in Ruby:
    class PointF < CStruct
      double:x
      double:y
    end

    # write file
    File.open("point.bin","wb")do |f|
        point   = Point.new {|st| st.x = 100; st.y =200 }
        point_f = PointF.new{|st| st.x = 20.65; st.y =70.86 }

        f.write point.data
        f.write point_f.data
    end

    #read file
    File.open("point.bin","rb")do |f|
        point   = Point.new
        point_f = PointF.new

        point   << f.read(Point.size)
        point_f << f.read(PointF.size)

        puts point.x
        puts point.y
        puts point_f.x
        puts point_f.y
    end