The type of data that a variable can store is specified by a data type. The type of data can be integer, floating, character, etc. In C# language, there are 3 types of data types.
| Types | Data Types |
| Value Data Type | short, int, char, float, double etc |
| Reference Data Type | String, Class, Object and Interface |
| Pointer Data Type | Pointers |
Value Data Type:
Both the integer-based and floating-point based data types are included in the value data types. Also, both the signed and unsigned literals are supported by the C# language. In C# language, there are 2 types of the value data type.
Predefined Data Types:
Example: Integer, Boolean, Float, etc.
User defined Data Types:
Example: Structure, Enumerations, etc.
According to the 32 or 64-bit operating system, the memory size of data types may also vary. Below we have listed the value data types with size according to the 32 bit OS.
| Data Types | Range | Memory Size |
| char | -128 to 127 | 1 byte |
| signed char | -128 to 127 | 1 byte |
| unsigned char | 0 to 127 | 1 byte |
| short | -32,768 to 32,767 | 2 byte |
| signed short | -32,768 to 32,767 | 2 byte |
| unsigned short | 0 to 65,535 | 2 byte |
| int | -2,147,483,648 to -2,147,483,647 | 4 byte |
| signed int | -2,147,483,648 to -2,147,483,647 | 4 byte |
| unsigned int | 0 to 4,294,967,295 | 4 byte |
| long | ?9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 | 8 byte |
| signed long | ?9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 | 8 byte |
| unsigned long | 0 – 18,446,744,073,709,551,615 | 8 byte |
| float | 1.5 * 10-45- 3.4 * 1038, 7-digit precision | 4 byte |
| double | 5.0 * 10-324- 1.7 * 10308, 15-digit precision | 8 byte |
| decimal | at least -7.9 * 10?28- 7.9 * 1028, with at least 28-digit precision | 16 byte |
Reference Data Type:
The actual data stored in a variable is not included in a reference data types. They only contain a reference to the variables. Thus a change in value is automatically reflected by the other variable when the data is changed by one of the variables. In C# language, there are 2 types of reference data types.
Predefined Data Types:
Example: Objects, String.
User-defined Data Types:
Example: Classes, Interface.
Pointer Data Type:
Being a variable, a pointer in C# language is used as a locator or an indicator to point to an address of a value.
Symbols used in pointer:
| Symbol | Name | Uses |
| & (ampersand sign) | Address operator | Used to determine the address of a variable. |
| * (asterisk sign) | Indirection operator | Used to access the value of an address. |
Declaring a pointer:
In C# language, the * (asterisk symbol) is used to declare a pointer.
Example:
int * x; //pointer to int
char * ch; //pointer to char