What are the Variables and Variable Types in C sharp

"Variables" are simply storage locations for data in program. Programmer is able to place data into variable and retrieve their contents. The interpretation of the data in a variable is controlled through "Types".

The C# simple types consist of the Boolean, Integrals, Floating Point, Decimal and String. In integrals types includes sbyte, byte, short, int, uint, long, and char.

In “Floating Point" refers to the float and double types


The Boolean Type
Boolean types are declared using the keyword, bool. They have two values: true or false.
          bool state = true;
        bool noState = false;


Integral Types
They are whole numbers, either signed or unsigned. Integral types are well suited for those operations involving whole number calculations.

The Size and Range of C# Integral Types

Type	Size (in bits)	Range
sbyte	8	-128 to 127
byte	8	0 to 255
short	16	-32768 to 32767
ushort	16	0 to 65535
int	32	-2147483648 to 2147483647
uint	32	0 to 4294967295
long	64	-9223372036854775808 to 9223372036854775807
ulong	64	0 to 18446744073709551615

Floating Point and Decimal Types

In C# floating point type is either a float or double. Floating point types are used when you need to perform operations requiring fractional representations.

The Floating Point and Decimal Types with Size, precision, and Range

Type	Size (in bits)	precision	Range
float	32	7 digits	1.5 x 10-45 to 3.4 x 1038
double	64	15-16 digits	5.0 x 10-324 to 1.7 x 10308
decimal	128	28-29 decimal places	1.0 x 10-28 to 7.9 x 1028

The string Type
A string is a collection of characters. This type allows us to manipulate character data through methods and properties. It provides methods to concatenate, append, replace, search and split.

String has the following characteristics

1. It is a reference type – string is not a value type. It is a reference type.
2. It's immutable - You can never change the contents of a string. If you try to do, it just sets the value of string to a new string, which is a copy of the old string.
3. It can contain nulls - In .NET, strings can contain null characters with no problems at all as far as the string methods themselves are concerned
4. It overloads by the == operator - When the == operator is used to compare two strings, the Equals method is called