Question

Is there a succinct way to represent a bounded numeric value in .NET 3.5?

By this I mean a value such as a percentage (0 – 100) probability (0 – 1) or stock level (0 or above).

I would want a ArgumentOutOfRangeException (or equivalent) to be thrown if an out-of-range assignment was attempted. I would also want static MaxValue and MinValue properties to be available.

It was suggested in a comment to another SO question that this was a good use of a struct.

Answer 1

I don’t think there is a built-in way like the Ada ‘range’ keyword, but you could easily create a type like RestrictedRange<T> that had a min and max value along with the current value:

public class RestrictedRange<T> where T : IComparable {             private T _Value;      public T MinValue { get; private set; }     public T MaxValue { get; private set; }      public RestrictedRange(T minValue, T maxValue)         : this(minValue, maxValue, minValue)     {     }      public RestrictedRange(T minValue, T maxValue, T value)     {         if (minValue.CompareTo(maxValue) > 0)         {             throw new ArgumentOutOfRangeException('minValue');         }          this.MinValue = minValue;         this.MaxValue = maxValue;         this.Value = value;     }      public T Value     {         get         {             return _Value;         }          set         {             if ((0 < MinValue.CompareTo(value)) || (MaxValue.CompareTo(value) < 0))             {                 throw new ArgumentOutOfRangeException('value');             }             _Value = value;         }     }      public static implicit operator T(RestrictedRange<T> value)     {         return value.Value;     }              public override string ToString()     {         return MinValue + ' <= ' + Value + ' <= ' + MaxValue;     } } 

Since there is an implicit conversion to automatically get the value, this will work:

var adultAge = new RestrictedRange<int>(18, 130, 21); adultAge.Value++; int currentAge = adultAge; // = 22 

In addition, you can do things like this

var stockLevel = new RestrictedRange<int>(0, 1000) var percentage = new RestrictedRange<double>(0.0, 1.0);