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  1. using System;
  2. public class Test
  3. {
  4.     // This example showcase the following characteristics:
  5.     //     (1) Choice of UoM (Unit of Measure) as Property get/set
  6.     //     (2) Named constructor for choice of UoM
  7.     //     (3) ToString support for UoM
  8.     //     (4) Roundtrip conversion (negligible rounding loss permitted
  9.     //         by double precision)
  10.     //     (5) Operator overloading (but lacking dimensional type check)
  11.     //
  12.     // Keep in mind this is just prototype code.
  13.  
  14.     public static void Main()
  15.     {
  16.         Length len = Length.FromFeet(8.0);
  17.         Console.WriteLine("feets: " + len.Feet.ToString("F15"));
  18.         Console.WriteLine("meters: " + len.Meters);
  19.         Console.WriteLine("tostring: " + len);
  20.         Console.WriteLine("tostring(ft): " + len.ToString("ft"));
  21.  
  22.         Length lenRT = Length.FromMeters(Length.FromFeet(Length.FromMeters(len.Meters).Feet).Meters);
  23.         Console.WriteLine("roundtrip (m): " + lenRT.ToString("F15"));
  24.         Console.WriteLine("roundtrip (ft): " + lenRT.ToString("ftF15"));
  25.         Console.WriteLine("roundtrip (ft): " + lenRT.Feet.ToString("F15"));
  26.  
  27.         Dimensioned sum1 = DimensionProduct.FromSum(len, lenRT);
  28.         Console.WriteLine("sum1: " + sum1);
  29.  
  30.         Dimensioned prod1 = DimensionProduct.FromProduct(len, lenRT);
  31.         Dimensioned prod2 = len * lenRT;
  32.         Console.WriteLine("product1: " + prod1);
  33.         Console.WriteLine("product2: " + prod2);
  34. 	}
  35.  
  36.     public interface Dimensioned
  37.     {
  38.         int[] DimensionIndicator { get; }
  39.         double Value { get; }
  40.     }
  41.  
  42.     public class DimensionProduct : Dimensioned
  43.     {
  44.         private int[] myIndicator = new int[] {0, 0, 0, 0, 0, 0, 0};
  45.         private double myValue = 0.0;
  46.         public int[] DimensionIndicator
  47.         {
  48.             get { return (int[]) myIndicator.Clone(); }
  49.         }
  50.         public double Value
  51.         {
  52.             get { return myValue; }
  53.         }
  54.         private DimensionProduct(int[] indicator, double value)
  55.         {
  56.             myIndicator = (int[])indicator.Clone();
  57.             myValue = value;
  58.         }
  59.         public static DimensionProduct FromProduct(Dimensioned a, Dimensioned b)
  60.         {
  61.             return new DimensionProduct(
  62.                 _ArrayAdd(a.DimensionIndicator, b.DimensionIndicator),
  63.                 a.Value * b.Value);
  64.         }
  65.         public static DimensionProduct FromSum(Dimensioned a, Dimensioned b)
  66.         {
  67.             if (!_ArraySame(a.DimensionIndicator, b.DimensionIndicator))
  68.             {
  69.                 throw new ArgumentException("Incompatible dimensions", "b");
  70.             }
  71.             return new DimensionProduct(a.DimensionIndicator,
  72.                 a.Value + b.Value);
  73.         }
  74.         private static int[] _ArrayAdd(int[] a, int[] b)
  75.         {
  76.             int len = Math.Min(a.Length, b.Length);
  77.             int[] result = new int[len];
  78.             for (int k = 0; k < len; ++k)
  79.             {
  80.                 result[k] = a[k] + b[k];
  81.             }
  82.             return result;
  83.         }
  84.         private static bool _ArraySame(int[] a, int[] b)
  85.         {
  86.             int len = Math.Min(a.Length, b.Length);
  87.             for (int k = 0; k < len; ++k)
  88.             {
  89.                 if (a[k] != b[k]) return false;
  90.             }
  91.             return true;
  92.         }
  93.         public override string ToString()
  94.         {
  95.             // This is a diagnostic implementation only; 
  96.             // we won't know how to properly format the string 
  97.             // for a generic dimension vector.
  98.             return myValue.ToString("F15") + " " + _ArrayStr(myIndicator);
  99.         }
  100.         private static string _ArrayStr(int[] arr)
  101.         {
  102.             return "{" + string.Join(",", Array.ConvertAll(arr, x => x.ToString())) + "}";
  103.         }
  104.     }
  105.  
  106.     public static class Constants
  107.     {
  108.         // note: scaling factors need to be as precise as permitted by 
  109.         // double-precision, to preserve precision in round-trip conversions.
  110.         public static double FeetToMeter = 0.3048000000; // exact
  111.         public static double MeterToFeet = 1.0 / 0.3048000000; // nearly exact
  112.     }
  113.  
  114.     public class Length : Dimensioned
  115.     {
  116.         public int[] DimensionIndicator 
  117.         { 
  118.             get { return new int[] { 0, 1, 0, 0, 0, 0, 0 }; }
  119.         }
  120.         public double Value
  121.         {
  122.             get { return myValue; }
  123.         }
  124.  
  125.         private double myValue;
  126.         public double Meters
  127.         {
  128.             get { return myValue; }
  129.             set { myValue = value; }
  130.         }
  131.         public double Feet
  132.         {
  133.             get { return myValue * Constants.MeterToFeet; }
  134.             set { myValue = value * Constants.FeetToMeter; }
  135.         }
  136.         public Length() {}  // default zero
  137.         private Length(double initValue) // made private to avoid ambiguity
  138.         {
  139.             myValue = initValue;
  140.         }
  141.         // unambiguous "named constructors"
  142.         public static Length FromMeters(double meter) 
  143.         {
  144.             return new Length(meter);
  145.         }
  146.         public static Length FromFeet(double feet)
  147.         {
  148.             Length len = new Length();
  149.             len.Feet = feet;
  150.             return len;
  151.         }
  152.         public override string ToString()
  153.         {
  154.             return ToString("");
  155.         }
  156.         public string ToString(string fmt)
  157.         {
  158.             bool useFeet = (fmt != null && fmt.StartsWith(
  159.                 "ft", StringComparison.InvariantCultureIgnoreCase));
  160.             if (useFeet)
  161.             {
  162.                 return Feet.ToString(fmt.Substring(2)) + " feet";
  163.             }
  164.             else 
  165.             {
  166.                 return Meters.ToString(fmt) + " meters";
  167.             }
  168.         }
  169.  
  170.         // Try both. The choice depends on whether one has enough time
  171.         // to create customized classes for each derived physical quantity 
  172.         // (such as the Area class)
  173. #if false 
  174.         public static DimensionProduct operator * (Length a, Length b)
  175.         {
  176.             return DimensionProduct.FromProduct(a, b);
  177.         }
  178. #else
  179.         public static Area operator * (Length a, Length b)
  180.         {
  181.             return Area.FromSquareMeters(a.Meters * b.Meters);
  182.         }
  183. #endif
  184.     }
  185.  
  186.     public class Area : Dimensioned
  187.     {
  188.         public int[] DimensionIndicator 
  189.         { 
  190.             get { return new int[] { 0, 2, 0, 0, 0, 0, 0 }; }
  191.         }
  192.         public double Value
  193.         {
  194.             get { return myValue; }
  195.         }
  196.         private double myValue;
  197.         public double SquareMeters
  198.         {
  199.             get { return myValue; }
  200.             set { myValue = value; }
  201.         }
  202.         public double SquareFeet
  203.         {
  204.             get { return myValue * Math.Pow(Constants.MeterToFeet, 2); }
  205.             set { myValue = value * Math.Pow(Constants.FeetToMeter, 2); }
  206.         }
  207.         public static Area FromSquareMeters(double sqm)
  208.         {
  209.             Area obj = new Area();
  210.             obj.SquareMeters = sqm;
  211.             return obj;
  212.         }
  213.         public static Area FromSquareFeet(double sqft)
  214.         {
  215.             Area obj = new Area();
  216.             obj.SquareFeet = sqft;
  217.             return obj;
  218.         }
  219.         public override string ToString() // for brevity I did not customize this
  220.         {
  221.             return myValue.ToString("F15") + " square meters";
  222.         }
  223.     }
  224. }
Success #stdin #stdout 0.06s 33984KB
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		 stdout
					

				
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feets: 8.000000000000000
meters: 2.4384
tostring: 2.4384 meters
tostring(ft): 8 feet
roundtrip (m): 2.438400000000000 meters
roundtrip (ft): 8.000000000000000 feet
roundtrip (ft): 8.000000000000000
sum1: 4.876800000000000 {0,1,0,0,0,0,0}
product1: 5.945794560000000 {0,2,0,0,0,0,0}
product2: 5.945794560000000 square meters


	

		
	 
	
	
			

					
			
			
			
			
			
			
			
			

			
			
			
		

	
		
		

			

			                        







			
			

				

	
					
					 https://ideone.com/x7hz7i
					
					
					
					
					

												
Prototyping an answer to http://p...content-available-to-author-only...e.com/questions/197416/data-structure-for-accessing-units-of-measure

												
						
						

					

					
					
					

						
language:

						
C# (gmcs 5.20.1)

					

					

						
created:
								
						
10 years ago

					

					

						
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