// NULL
public void WorkingWithNull()
{
PointC p = null;
Console.WriteLine(p == null); // => true
// The following oline generates a runtime error
// (a NullReferenceException is throw):
Console.WriteLine(p.X);
// In contrast, a value type cannot ordinarily have a null value:
// PointS p2 = null; // Compile-time error
// int x = null; // Compile-time error
}
// REFERENCE TYPES
public void ReferenceTypes()
{
PointC p1 = new PointC();
p1.X = 7;
PointC p2 = p1; // Copies p1 reference
Console.WriteLine(p1.X); // => 7
Console.WriteLine(p2.X); // => 7
p1.X = 9; // Change p1.X
Console.WriteLine(p1.X); // => 9
Console.WriteLine(p2.X); // => 9
}