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C# in a Nutshell by Peter Drayton, Ted Neward, Ben Albahari

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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, char, bool)

  • 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

This table lists the integral types and their features:

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. 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

UL

ulong

Integral conversions

An implicit conversion between integral types is permitted when the type to convert to contains every possible ...

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