Recipe 3.1. Creating Union-Type Structures
Problem
You need to create a data type that behaves like a union type in C++. A union type is useful mainly in interop scenarios in which the unmanaged code accepts and/or returns a union type; we suggest that you do not use it in other situations.

Solution
Use a structure and mark it with the StructLayout attribute (specifying the LayoutKind.Explicit layout kind in the constructor). In addition, mark each field in the structure with the FieldOffset attribute. The following structure defines a union in which a single signed numeric value can be stored:

Recipe 3.2. Allowing a Type to Represent Itself as a String
Problem
Your class or structure needs to control how its information is displayed when its ToString method is called. In addition, you need to apply different formats to this information. For example, when creating a new data type, such as a Line class, you might want to allow objects of this type to be able to display themselves in a textual format. In the case of a Line object, it might display itself as (x1, y1)(x2, y2).

Solution
Override and/or implement the IFormattable.ToString method to display numeric information, such as for a Line structure:

Recipe 3.3. Converting a String Representation of an Object into an Actual Object
Problem
You need a way of accepting a string containing a textual representation of an object and converting it to an object usable by your application. For example, if you were provided with the string representation of a line (x1, y1)(x2, y2), you would want to convert it into a Line structure.

Solution
Implement a Parse method on your Line structure:

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