How to initialize generic parameter type T?

Question

Simple question:
If you have a string x, to initialize it you simple do one of the following:

string x = String.Empty;  

or

Answer 1

You have two options:

You can constrain T: you do this by adding: where T : new() to your method. Now you can only use the someMethod with a type that has a parameterless, default constructor (see Constraints on Type Parameters).

Or you use default(T). For a reference type, this will give null. But for example, for an integer value this will give 0 (see default Keyword in Generic Code).

Here is a basic console application that demonstrates the difference:

using System;

namespace Stackoverflow
{
    class Program
    {
        public static T SomeNewMethod()
            where T : new()
        {
            return new T();
        }

        public static T SomeDefaultMethod()
            where T : new()
        {
            return default(T);
        }

        struct MyStruct { }

        class MyClass { }

        static void Main(string[] args)
        {
            RunWithNew();
            RunWithDefault();
        }

        private static void RunWithDefault()
        {
            MyStruct s = SomeDefaultMethod();
            MyClass c = SomeDefaultMethod();
            int i = SomeDefaultMethod();
            bool b = SomeDefaultMethod();

            Console.WriteLine("Default");
            Output(s, c, i, b);
        }

        private static void RunWithNew()
        {
            MyStruct s = SomeNewMethod();
            MyClass c = SomeNewMethod();
            int i = SomeNewMethod();
            bool b = SomeNewMethod();

            Console.WriteLine("New");
            Output(s, c, i, b);
        }

        private static void Output(MyStruct s, MyClass c, int i, bool b)
        {
            Console.WriteLine("s: " + s);
            Console.WriteLine("c: " + c);
            Console.WriteLine("i: " + i);
            Console.WriteLine("b: " + b);
        }

    }
}

It produces the following output:

New
s: Stackoverflow.Program+MyStruct
c: Stackoverflow.Program+MyClass
i: 0
b: False
Default
s: Stackoverflow.Program+MyStruct
c:
i: 0
b: False