Variables and its Data Types

In practical life nobody can carry each and every file, folders or documents with himself except of those which he uses them very frequently or is very important but for those who are not important he need any place like drawer or cabinets to store them and can reuse them whenever he needs. In the same way .Net framework also need any place to store things and can reuse them, these places are called Variables. Variable store values of some specific type and these types are called Data Type. There are various types of data type like integer, float or string.

In order to store any numeric value .Net gives us various types like byte, sbyte, short, ushort, int, uint, long, ulong, float, double from which only float and double can carry decimal values and rest of them can only carry whole number. There are different ranges of maximum and minimum values for different types that they can hold. These ranges depends on the spaces (in bytes) occupied by variables of specific type in the memory.

Byte and sbyte occupies one byte in the memory and it ranges from 0 to 255 and -128 to 127 respectively. The only difference between byte and sbyte is that byte can not carry signed values and sbyte can.

27

26

25

24

23

22

21

20

                     Byte

Short and ushort occupies two bytes in the memory and it ranges from -32768 to 32767 and 0 to 65535 respectively. The only difference between short and ushort is that short can carry signed values and ushort can not.

27	26	25	24	23	22	21	20
215	214	213	212	211	210	29	28

                     Short

Int and uint occupies four bytes in the memory and it ranges from -2147483648 to -2147483648 and 0 to 4294967295 respectively. The only difference between int and uint is that int can carry signed values and uint can not.

27	26	25	24	23	22	21	20
215	214	213	212	211	210	29	28
223	222	221	220	219	218	217	216
231	230	229	228	227	226	225	224

                     Int

Table given below give the list ranges and bytes occupied by the variable of different type:

Data Type	Size in Bytes	Minimum Range	Maximum Range
sbyte	1	-128	127
byte	1	0	255
short	2	-32768	32767
ushort	2	0	65535
int	4	-2147483648	2147483647
uint	4	0	4294967295
long	8	-9223372036854775808	9223372036854775807
ulong	8	0	18446744073709551615
double	8	-1.79769313486232E+308	1.79769313486232E+308
decimal	16	-79228162514264337593543950335	79228162514264337593543950335

In the same way .Net also gives string data type to store alphanumeric data. String occupies 20 plus bytes means initially it occupies 20 bytes but when maximum value of its range reaches it will increases its bytes. If we store numeric value in string type it will not consider it as numeric, it will be considered as string (but .Net gives various methods to convert string in integer and other numeric value types).