AcornPublishing_essential-csharp-7e/EssentialCSharp-8.0/src/Chapter12/Listing12.04.DeclaringVersionsOfVariousValueTypesThatStoreNull.cs
namespace AddisonWesley.Michaelis.EssentialCSharp.Chapter12.Listing12_04
{
    using System;

    struct NullableInt
    {
        /// <summary>
        /// Provides the value when HasValue returns true
        /// </summary>
        public int Value { get; private set; }

        /// <summary>
        /// Indicates whether there is a value or whether
        /// the value is "null"
        /// </summary>
        public bool HasValue { get; private set; }

        // ...
    }

    struct NullableGuid
    {
        /// <summary>
        /// Provides the value when HasValue returns true
        /// </summary>
        public Guid Value { get; private set; }

        /// <summary>
        /// Indicates whether there is a value or whether
        /// the value is "null"
        /// </summary>
        public bool HasValue { get; private set; }

        // ...
    }

    // ...
}
