C# in a Nutshell, Second Edition

Predefined Types

This section explains each of C#’s predefined types:

• Value types

  —Integer, signed (sbyte, short, int, long)

  —Integer, unsigned (byte, ushort, uint, ulong)

  —Floating-point (float, decimal, double)

• Reference types

  —Object

  —String

All of these types alias types found in the System namespace. For example, there is only a syntactic difference between these two statements:

int i = 5;
System.Int32 i = 5;

Integral Types

C# type	System type	Size	Signed
sbyte	System.SByte	1 byte	yes
short	System.Int16	2 bytes	yes
int	System.Int32	4 bytes	yes
long	System.Int64	8 bytes	yes
byte	System.Byte	1 byte	no
ushort	System.UInt16	2 bytes	no
uint	System.UInt32	4 bytes	no
ulong	System.UInt64	8 bytes	no

For unsigned integers that are n bits wide, possible values range from 0 to 2^n-1. For signed integers that are n bits wide, their possible values range from -2^n-1 to 2^n-1-1. Integer literals can use either decimal or hexadecimal notation:

int x = 5;
ulong y = 0x1234AF; // prefix with 0x for hexadecimal

When an integral literal is valid for several possible integral types, the default type chosen goes in this order: int, uint, long, and ulong. The following suffixes may be used to explicitly specify the chosen type:

U

uint or ulong

L

long or ulong

U

ulong

Integral conversions

An implicit conversion between integral types is permitted when the type to convert to contains every possible value of the type to convert from. Otherwise an explicit ...