NET Basic Course--type foundation (NET Beauty)

1. Type: value type reference type.

Classification by: How the type is allocated in memory. The value type is on the stack, and the reference type is in the managed heap.

noun : Stack-All variables are allocated on the stack, except that the value type directly contains the data, and the reference type contains an address that points to the managed heap object.

A variable that contains the address of an object on a heap is called a variable that refers to this object or variable that references this object .

value type : Simple Type (base Class library type alias) int byte etc.

Declaring an int type is actually a struct-type variable that declares a System.Int32 that contains all the fields in the value type (here, the struct)

Structure Enumeration

Reference type : Class delegate interface, etc.

2. Initialization of variables

 Public struct Point    {        publicint  x;    }     class program    {        staticvoid Main (string[] args)        {point            p;// The struct type variable itself is an instance of            Console.WriteLine (p.x); // compiler hints may refer to Unassigned fields x   should be preceded by p.x=10;             Console.readkey ();        }    }

But there is another situation that passes directly and prints out 0. Note the difference. The reason is that the fields are also initialized when the class is initialized .

 Public class Point    {        publicint  x;    }     class program    {        staticvoid Main (string[] args)        {            new point ();//Note this  must be initialized first, otherwise the compiler prompts for an unassigned local variable            Console.WriteLine (p.x);            Console.readkey ();        }    }

3. Object references are not set to an instance of an object, as shown in the following example. The reason for this is that a is an object reference, and no new has been pointed to any actual object.

Object A = null; Console.WriteLine (A.tostring ());

NET Basic Course--type foundation (NET Beauty)