What is DataType?
A data type in a programming language is a set of data with values having predefined characteristics. It describes how the value will be stored for the type and how it will be processed.
DataTypes in c#:
The C# programming language is a strongly typed language. All variables must be declared with a valid data type.
Types of DataTypes:
There are two types of datatype:
1. Built In data type
2. User Defined data type
Built In data type:
The built in data types are provided by the c# .NET frameword. The data types are reserved keywords and cannot be used as a variable name.
Built in data types supported in c# are:
byte - 0 to 255 characters
sbyte(short byte) - (-128 to 127)
short - 32,768 to 32,767
ushort(unsigned short) - 0 to 65,535
int -2,147,483,648 to 2,147,483,647
uint(unsigned int) 0 to 4,294,967,295
long -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
ulong 0 to 18,446,744,073,709,551,615
float - (-3.402823e38 to 3.402823e38 )
double - ( -1.79769313486232e308 to 1.79769313486232e308 )
decimal ( -79228162514264337593543950335 to 79228162514264337593543950335 )
char - A Unicode character.
string - A string of Unicode characters.
bool - True or False.
object - An object.
User Defined data type
The user defined data type, will be defined by the user.
Example:
Class or Interface
Enumerations - user defined integer type
The data types can further be classified into
a) Value Types
b) Reference Types
Value Types:
The value type variables store the actual data in the variable. Each variable maintains its own copy of data.
Example:
int x = 10;
double y = 10.12;
char z = 's';
The following value types are supported in c#:
* int
* uint
* bool
* char
* decimal
* float
* double
* sbyte
* byte
* char
* short
* ushort
* ulong
* long
* decimal
* structs
* enumerations
Reference Types
Reference types variables store the reference of the actual data.
The following reference types are supported in c#.
* string - represents a string of unicode characters.
* object - Represents a general purpose type. In C#, all predefined and user-defined types inherit from the object type or System.Object class.
* class
* interface
* delegate
Example:
string s = "TestString";
Although string is a reference type, the equality operators (== and !=) are defined to compare the values of string objects, not references.
public delegate void TestDelegate(string message);
The delegate keyword is used to declare a reference type that can be used to encapsulate a named or an anonymous method
Data Type Conversions:
C# supports two types of conversions.
1. Implicit conversions
2. Explicit conversions.
Implicit conversions are direct conversion. It includes method invoking and assignment.
For example:
int iVal = 34;
long lVal = intValue;
Explicit conversions includes type casting. By using a cast expression for conversion.
For example:
long lVal = 123456;
int iVal = (int) lVal;
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| Author: Prasoon Kumar 30 Jun 2009 | Member Level: Silver Points : 1 |
Try,
to add few things about Resource allocation of the referance
types and value types.
regards
Prasoon
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