Built-in C# Data Types

01/08/2014
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C# is a strongly-typed language. Before a value can be stored in a variable, the type of the variable must be specified, as in the following examples:

int a = 1;
string s = "Hello";
XmlDocument tempDocument = new XmlDocument();

 

Note that the type must be specified both for simple, built-in types such as an int, and for complex or custom types such as XmlDocument.

 

C# includes support for the following built-in data types:

Data Type

Range

byte

0 .. 255

sbyte

-128 .. 127

short

-32,768 .. 32,767

ushort

0 .. 65,535

int

-2,147,483,648 .. 2,147,483,647

uint

0 .. 4,294,967,295

long

-9,223,372,036,854,775,808 .. 9,223,372,036,854,775,807

ulong

0 .. 18,446,744,073,709,551,615

float

-3.402823e38 .. 3.402823e38

double

-1.79769313486232e308 .. 1.79769313486232e308

decimal

-79228162514264337593543950335 .. 79228162514264337593543950335

char

A Unicode character.

string

A string of Unicode characters.

bool

True or False.

object

An object.

These data type names are aliases for predefined types in the System namespace. They are listed in the section Built-In Types Table (C# Reference). All these types, with the exception of object and string, are value types.

Sample Types of Variables

Let’s take a look at the common variable types that we’ll see in a C# program, and discuss the differences between them, and when you’ll use them.

Here is a table containing the main variable types in C#:

Type Name Description Bytes Data Range Example
short stores smaller integers 2 -32,768 to 32,767 short score = 495;
int stores medium sized integers 4 -2,147,483,648 to 2,147,483,647 int score = 450000;
long stores very large integers 8 –9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 long highScore = 4043333;
byte stores small unsigned (no + or -) integers 1 0 to 255 byte color = 55;
ushort stores small unsigned integers 2 0 to 65,535 ushort score = 495;
uint stores medium unsigned integers 4 0 to 4,294,967,295 uint score = 4500000;
ulong stores large unsigned integers 8 0 to 18,446,744,073,709,551,615 ulong highScore = 4043333;
float stores smaller real (floating point) numbers 4 ±1.5 × 10^−45 to ±3.4 × 10^38, 7 digits of accuracy float xPosition = 3.2f;
double stores larger real numbers 8 ±5.0 × 10^−324 to ±1.7 × 10^308, 15 to 16 digits of accuracy double yPosition = 3.3;
decimal real numbers, smaller range, higher accuracy 16 ±1.0 × 10^−28 to ±7.9 × 10^28, 28 to 29 digits of accuracy decimal zPosition = 3.3;
char stores a single character or letter 2 any single character char myFavoriteLetter = ‘c’;
string stores a sequence of numbers, letters, or symbols any a sequence of any character of any length string message = “Hello World!”
bool stores a true or false value 1 true or false bool levelComplete = true;

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Programming
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