What does default(object); do in C#?

Googling is only coming up with the keyword, but I stumbled across some code that says

MyVariable = default(MyObject);

and I am wondering what it means...

---

For a reference-type, it returns null

For a value-type other than Nullable<T> it returns a zero-initialized value

For Nullable<T> it returns the empty (pseudo-null) value (actually, this is a re-statement of the second bullet, but it is worth making it explicit)

The biggest use of default(T) is in generics, and things like the Try... pattern:

bool TryGetValue(out T value) {
    if(NoDataIsAvailable) {
        value = default(T); // because I have to set it to *something*
        return false;
    }
    value = GetData();
    return true;
}

As it happens, I also use it in some code-generation, where it is a pain to initialize fields / variables - but if you know the type:

bool someField = default(bool);
int someOtherField = default(int)
global::My.Namespace.SomeType another = default(global::My.Namespace.SomeType);

---

default keyword will return null for reference types and zero for numeric value types.

For struct s, it will return each member of the struct initialized to zero or null depending on whether they are value or reference types.

from MSDN

Simple Sample code :<br>
    class Foo
    {
        public string Bar { get; set; }
    }

    struct Bar
    {
        public int FooBar { get; set; }
        public Foo BarFoo { get; set; }
    }

    public class AddPrinterConnection
    {
        public static void Main()
        {

            int n = default(int);
            Foo f = default(Foo);
            Bar b = default(Bar);

            Console.WriteLine(n);

            if (f == null) Console.WriteLine("f is null");

            Console.WriteLine("b.FooBar = {0}",b.FooBar);

            if (b.BarFoo == null) Console.WriteLine("b.BarFoo is null");

        }
    }

OUTPUT:

0
f is null
b.FooBar = 0
b.BarFoo is null

---

Specifies the default value of the type parameter.This will be null for reference types and zero for value types.

See default

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