Data type specifies size of the data and type of data.
C#.net data type are divided into two types
Int i = 0
I 10 (7000)
C language C#
Int * p = i
p 7000 (9000)
Value type will be created at compile time and these will be started in STACK memory.
Value types holds the data directly
No default value for value type
GC (Garbage collector) cannot access stack memory . that is GC can not clears stack run time
Pre-defined data types
Reference Type will be created at run time and these will be stored in HEAP memory.
Reference Type holds the reference but not the data.
Reference Type holds the default value.
GC can access HEAP memory.
Var (newly introduced)
Working with Predefined Data types
These are divided in to 4 groups
Group 1 :- Integral Data type
.byte 1 byte 0 255
.S byte 1 byte -128 to +127
.Short 2 bytes -32768 to +32768
.U short 2 bytes 0 – 65535
Int 4 bytes ~ +- 214 cores
U int 4bytes 0 -~ 429 cores
Long 8 bytes + 2^63
U Long 8 bytes 0 – 2 ^ 64 -1
Group 2 :- Floating Related Data Types
*float 4 B
*double 8 B
*decimal 16 B
Group 3 :- character Related Data types
.char 2 B : char holds UNICODE (universal coding) characters which are required for globalization.
.String 16 B : 4 GB
Group 4 :- other Data type
.bool 1 B true/ false
.Data time 12 B
1/1/0001 to 31/12/9999
Syntax to declare a variable
<Data type> var name = value;
Note:- In C# .net always variable name need to be started either with alphabet, underscore, @ symbol
Int a =90;
Int – a = 90;
Int @a = 90;
Int *a = 90;
Int 2a = 90;
Int if = 90;
Example on Data Types
Open console Application project .
Write the following code in main method.
Int I = 90;
Console. Write Line (i);
Float x = 4.0 f
Console. Write Line (x);
Byte b1 = 10, b2 = 20;
Int c = b1 + b2;
Console. Write Line (c);
Console. Write Line ();
Execute the project :(f5)
value types must be initialized before using
float X = 4.0 gives an error
By default 4.0 will be treated as double;
Solution: - float x = 4. 0 F (or) float X = 4. 0f;
A number, which is post fixed with f @ F is called as float.
A number, which is post fixed with d @ D is called as double.
A number, which is post fixed with m@ M is called as decimal.
Byte c = b1 + b2, gives an error + operator returns the result in the format of int.