Default-'key' in generics'

Msdn definition:

One problem that occurs in generic classes and generic methods is how to assign the default value to parameterized type T when the following conditions are unknown:

• T is the reference type or value type.

• If T is of the value type, whether it is a value or a structure.

Given a variable T of the parameterized type t, the Statement T = null is valid only when t is of the reference type; only when T is of the numerical type rather than the structure, statement t = 0 can be used normally. The solution is to use the default keyword, which returns null for the reference type and zero for the value type. For the structure, this keyword returns each structure member whose Initialization is zero or null, depending on whether the structure is a value type or a reference type. For a value type that can be null, System. Nullable <T> is returned by default, which is initialized like any structure.

Examples are also provided. The example is perfect.

There is also an extended usage ):

Console. WriteLine (null = default (List <int> ));
Console. WriteLine (default (int ));

Console. WriteLine (default (bool ));

Returns true, 0, and false.