Value Type

Saantosh
Posted by in .NET Framework category on for Beginner level | Views : 4121 red flag

Value types are derived implicitly from the System.ValueType base type. Value types are variables that contain their data directly instead of containing a reference to the data stored in memory. Instances of value types are stored in memory called the stack, where the runtime can create, read, update, and remove them quickly.
Value Type

Value types are derived implicitly from the System.ValueType base type. Value types are variables that contain their data directly instead of containing a reference to the data stored in memory. Instances of value types are stored in memory called the stack, where the runtime can create, read, update, and remove them quickly.

There are three types.

1. Built-in types
2. User-defined types
3. Enumerations
 

Built-in types

 
All built-in numeric types are value types. A numeric type based on the size of the values.


Type (VB/C#)

.NET Framework

Bytes

Range

Use for

SByte/sbyte

System.SByte

 

1

–128 to 127

Signed bytes

 

Byte/byte

System.Byte

 

1

0 to 255

Unsigned bytes

Short/short

System.Int16

2

–32768 to 32767

Interoperation and other specialized uses

Integer/int

System.Int32

4

–2147483648 to 2147483647

Whole numbers

(UInteger/uint)

System.UInt32

4

0 to 4294967295

Positive whole numbers

Long/long

System.Int64

 

8

–223372036854775808  to

9223372036854775807

Large whole numbers

Single/float

System.Single

4

–3.402823E+38 to 3.402823E+38

 

Floating point numbers

Double/double

System.Double

8

–1.79769313486232E+308 to

1.79769313486232E+308

large floating point numbers

Decimal/decimal

System.Decimal

16

–79228162514264337593543950335 to

79228162514264337593543950335

Financial and scientific calculations

Other Value Types

Char/char

System.Char

2

N/A

Single characters

Boolean/bool

System.Boolean

4

N/A

True/False

Date/date

 

System.DateTime

 

8

1/1/0001 12:00:00 AM

 To

12/31/9999 11:59:59 PM

Date Time

 

 

System.Guid

 

 

globally unique identifier, 128-bit

 

 

 

 

 

 


How to Declare Value Types

Value types are an implicit constructor declaring them instantiates the type automatically, you don’t have to include the new keyword. The constructor assigns a default value (null or 0), but you should always explicitly initialize the variable within the declaration.
Eg:-
 
//C#
bool b=false;
 
'VB.Net
Dim b As Boolean = False

How to Create User-Defined Types
 
User-defined types are also called structures or struct. Value type local instances are allocated on the stack and they contain their data directly. In other ways, structures nearly behave like classes.
structures by using the Structure keyword in VB. And  the struct keyword in  C#.

For Eg: -

class Test
{
    struct Emp
    {
        public int ID;
        public double Salary;
    };
 
    static void Main()
    {
        Simple s;
        s.ID = 1;
        s. Salary = 15520.50;
    }
}

How to Create Enumerations

Enumerations (enum)  are  a value type with a set of related symbols that have fixed values. Use enumerations to provide a list of choices for developers using your class. The purpose of enumerations is to simplify coding and improve code readability by meaningful name instead of simple numeric values.

Eg :

VB.NET

Enum Days as Integer
Monday

Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday

End Enum

C#

enum Days : int { Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday };


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About the Author

Saantosh
Full Name: santosh kumar
Member Level: Starter
Member Status: Member
Member Since: 9/2/2009 4:38:44 AM
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http://www.operativesystems.com

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