C# Data Types


C# is a strongly-typed language and we must declare the type of a variable that indicates the kind of values it is going to store, such as integer, float, decimal, text, etc.

The types of C# language are divided into two main categories.

  • Value types
  • Reference types.

Value Types

A value type holds a data value within its own memory space and it directly contains the values. Let's take the following example

int num = 99;

The system will stores 99 in the memory space allocated for the variable num.

The value types include simple types such as, int, float, bool, and char, enum, struct, and Nullable value types. These data types are called primitive (built-in types), because they are embedded in C# language at the lowest level.

Data Type Description Range
byte 8-bit unsigned integer 0 to 255
sbyte 8-bit signed integer -128 to 127
short 16-bit signed integer -32,768 to 32,767
ushort 16-bit unsigned integer 0 to 65,535
int 32-bit signed integer -2,147,483,648 to 2,147,483,647
uint 32-bit unsigned integer 0 to 4,294,967,295
long 64-bit signed integer -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
ulong 64-bit unsigned integer 0 to 18,446,744,073,709,551,615
float 32-bit Single-precision floating point type -3.402823e38 to 3.402823e38
double 64-bit double-precision floating point type -1.79769313486232e308 to 1.79769313486232e308
decimal 128-bit decimal type for financial and monetary calculations (+ or -)1.0 x 10e-28 to 7.9 x 10e28
char 16-bit single Unicode character Any valid character, e.g. a,*, \x0058 (hex), or\u0058 (Unicode)
bool 8-bit logical true/false value True or False
object Base type of all other types.
string A sequence of Unicode characters
DateTime Represents date and time 0:00:00am 1/1/01 to 11:59:59pm 12/31/9999

Reference Types

The reference type contains a pointer to another memory location that holds the data. It doesn't store its value directly unlike value types, but it stores the address where the value is being stored. The reference types include class, interface, delegate, and array types.

string message = "Welcome to C# Tutorial.";

The system will select a random location in memory for the variable message. The value of a variable message is the memory address of the actual data value.

Thus, reference type stores the address of the location where the actual value is stored instead of the value itself.