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Learning C# 2005, 2nd Edition by Brian MacDonald, Jesse Liberty

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Types

C# is a strongly typed language. That means that every object you create or use in a C# program must have a specific type (e.g., you must declare the object to be an integer or a string or a Dog or a Button). Essentially, the type indicates how big the object is (in memory) and what it can do.

Types come in two flavors: those that are built into the language (intrinsic types ) and those you create (classes and interfaces, discussed in Chapters 7 and 13). C# offers a number of intrinsic types, shown in Table 3-1.

Table 3-1. The intrinsic types

C# type

Size (in bytes)

.NET type

Description

byte

1

Byte

Unsigned (values 0-255).

char

2

Char

Unicode characters.

bool

1

Boolean

True or false.

sbyte

1

SByte

Signed (values -128 to 127).

short

2

Int16

Signed (short) (values -32,768 to 32,767).

ushort

2

UInt16

Unsigned (short) (values 0 to 65,535).

int

4

Int32

Signed integer values between -2,147,483,648 and 2,147,483,647.

uint

4

UInt32

Unsigned integer values between 0 and 4,294,967,295.

float

4

Single

Floating point number. Holds the values from approximately +/−1.5 * 10−45 to approximately +/−3.4 * 1038 with 7 significant figures.

double

8

Double

Double-precision floating point; holds the values from approximately +/−5.0 * 10−324 to approximately +/−1.8 * 10308 with 15–16 significant figures.

decimal

12

Decimal

Fixed-precision up to 28 digits and the position of the decimal point. This is typically used in financial calculations. Requires the suffix “m” or “M.”

long

8

Int64

Signed integers ...

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