// DATA TYPES
//
// Built-In Types(Simple)
// -Numeric
// -Character
// -Boolean
//
// Custom Types(Complex)
// -Structures
// -Classes
// -Interfaces
// -Enumerations
//
// Common Type System
// -Each type is either a value type or a reference type
// -Supports inheritance
// -Value types derive from System.ValueType
// -All types ferive from System.Object
//
// Value Types
// -Built-in types
// -Structures
// -Enumerations
// -Stored on the stack
// -Passed by value(a copy)
//
// Reference Type
// -Classes
// -Interfaces
// -Stored on the heap
// -Passed by reference(memory address)
// -Changing modifies original value
原文：http://www.cnblogs.com/yoghourt/p/4044187.html