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Sunday, September 1, 2013

What is the Data Type how to declare datatype in Asp.net with C#

Data Type in C# with  ASP.Net :


Basic Introduction of C# 


Data type, In this post you will learn what is Data type C# and how many data type in C#. There are many  types of C# data types(which type of data), according to their sizes and storing capacities and stringent basically 2 type we discus here:

  • Value Type:
  • Reference Type:

Value Type data Type:



C# is a strongly  language. It means, that you can not use variable (which store value ) without data types. Data types tell the compiler(converter) that which type of data is used in logic(program). Such as if you want to work in asp.net with string value then you will assign string  variable to work with. 

C# has  two types of data types: 

Reference Types:

Conceptually, a reference type represents a potentially large piece of data that is passed around a program via a reference to that data.  Reference types tend to be more complex in nature than value types.
Reference types have three major traits of their own:
  • Copy-by-reference semantics
  • Identity equality semantics
  • Heap memory allocation.

When an instance of a reference type is passed around in a program, a reference (i.e. a small, unique identifier) to the instance’s data is created.  The data itself is not copied. Finally, when the copied instance is edited, what’s actually being edited is the original data.
When two instances of a reference type are checked for equality, the two instances are considered equal only if they both point to the same piece of data (i.e. point to the same memory address).
In C#, reference types are allocated on the heap rather than the stack (i.e. opposite of value types).  Depending on the usage of the type, this could affect performance, although in most cases it’s not likely to matter.

It’s also worth noting that C# supports user-defined reference types.  These are called classes.  Classes allow you to define custom fields and methods on a reference type.

Value types:

Conceptually, a value type represents a very simple of data (number like 123 or a character like P).  In C#, value types have three major traits.

A Value type data type stores copy  the value whereas the Reference type data types stores the memory location  of the value. C sharp provides many  predefined  for working with ASP.NET, but it also provide power to user that's user create user defined data type when user need .

When an instance of a value type is passed around in a program, it is copied each time.  When a copy is edited, the original version does not change.
In C#, value types are allocated on the stack.

Deceleration of data:

<data type><variable name>=<value>

here datatype refer which type of data store in this variable.
variable name refer 'A NAME OF MEMORY LOCATION where data is store .
value refer what is the value which is store in this given variable 

Example of DATA Type :


1. String string1="parijat";
         here string1 is a variable which octane a string type (data type) value "parijat";
2. int number1=10;
         here number1 is a variable which canted  a integer type value 10;

similarly we can defined many type of data and then perform action Programming logic .

since we see that C sharp is not very typical its a very sample Programming language .


In next post we learn how to make a sample program in asp.net with C# and some other logical examples 

Type

Range

Size

bool
true/false
1 byte
byte
-128 to 127
1 byte
sbyte
0 to 255
1 byte
char
unicode; 0×0000 to 0xFFFF
2 bytes
ushort
0 to 65535
2 bytes
short
-32768 to 32767
2 bytes
uint
0
to
4,294,967,295
4 bytes
int
-2,147,483,648
to
2,147,483,647
4 bytes
ulong
0
to
18,446,744,073,709,551,615
8 bytes
long
–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
8 bytes
float
-3.4 × 1038
to
3.4 × 1038
4 bytes
double
±5.0 × 10−324
to
±1.7 × 10308
8 bytes
decimal
(-7.9 x 1028 to 7.9 x 1028) / (100 to 28)
16 bytes
struct
varies / user-defined
varies / user-defined