Data Types And Type Conversion In C#

 C# Data Types-  

  There are two types of data type in C#.


1. Primitive (Predefine)
2. Non-Primitive (User Defined)


Primitive data types

byte

short

int

float

double

long

char

bool

datetime

string

object

Non-primitive data types

class

struct

enum

interface

delegate

array

Integer Type:

 C# supports eight predefined integer types:

Name      CTS Type            Description                      Range                   sbyte    System.SByte     8-bit signed integer        -128 to 127 (-27 to 27-1)

short     System.Int16      16-bit signed integer       -32768 to 32767 (-215 to 215-1)

int         System.Int32      32-bit signed integer        -2147483648 to

                                                                                 2147483647 (-231 to 231-1)

long      System.Int64       64-bit signed integer       -9223372036854775808 to

                                                                                 9223372036854775807 (-263 to 263-1)

byte     System.Byte        8-bit unsigned integer      0 to 255 (0 to 28-1)

ushort  System.UInt16    16-bit unsigned integer     0 to 65535 (0 to 216-1)

uint      System.UInt32     32-bit unsigned integer    0 to 4294967295 (0 to 232-1)

ulong    System.UInt64    64-bit unsigned integer   0 to 18446744073709551615 (0 to 264-1)

Floating Point Type

Name                            CTS Type                               Description           
float                                   System.Single             32-bit single precision floating point

double                               System.Double           32-bit single precision floating point

Decimal Type

Name                            CTS Type                                 Description              

decimal                              System.Decimal        128-bit high precision decimal notation

Boolean type

Name                            CTS Type                                Value               

bool                                  System.Boolean                                true and false

Character Type

Name                             CTS Type                                Value              

char                                  System.Char                Represents a single 16-bit (Unicode                                                                                         character)

C# supports two predefined Reference Type

Name                                CTS Type                                Value                

object                                System.Object           The root type, from which all other types in                                                                                the CTS derive (including value type)

string                                 System.String             Unicode character string

In .NET Microsoft has divided data types in two parts:

1.  Value Type (Fixed in size)
2.  Reference Type (Not fixed in size)
In application context, value types are stored in stack but reference types are stored in managed heap. 

Value Type:

Value types are fixed in size.
Value types are made in system stack.
Actual values of data are stored in stack.
If you assign a value of a variable to another it will create two copies.

Reference Type 

Reference types are not fixed in size.
They are maintained in system managed heap but it also uses stack to store reference of heap.
Two primitive types (string and object) and non-primitive data types (class, interface & delegate) are examples of reference type.

CLR manages heap (large memory area). Heap address is accessed from stack. In reference type reference is used for processing using both managed heap and stack (operational entity).

C# type conversions

Conversion is the process of changing the value of one Type to another. System.Convert class provides a complete set of methods for supported conversions.

There are two types of conversions:

1.  Implicit Conversion

2.  Explicit Conversion

Implicit Conversion

implicit conversion autometically done by the compiler .

Explicit Conversion

In Explicit conversion programmer ask the compiler to convert the value into another data type means we can do explicit conversion forcefully.

Ex:

        int a = 5;

        object obj = a;   // Implicit Conversion

        int j;

        j =(int)obj;         //  Explicit Conversion