Structs - Illustrated C# 2005 - page 290

You can also create an instance of a struct without using the new operator. If you do this,
however, there are several restrictions—you cannot

￿ Use the value of a data member until you have explicitly set it

￿Ca l any function member until all the data members have been assigned

For example, the following code shows two instances of struct Simple created without
using the new operator. When there is an attempt to access s1 without explicitly setting the data
member values, the compiler produces an error message. There are no problems reading from
s2 after assigning values to its members.

struct Simple
{
public int x;
public int y;
}

class Program
{
static void Main()
{ No constructor calls
↓
Simple s1, s2;
Console.WriteLine("{0},{1}", s1.x , s1.y ); // Compiler error
↑ ↑
Not yet assigned
s2.x = 5;
s2.y = 10;
Console.WriteLine("{0},{1}", s2.x, s2.y); // OK
}
}