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. In other words, you must declare the object to be an integer or a string or a Dog or a Button. Essentially, the type indicates the characteristics of the object and what it can do.

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

Table 3-1. The intrinsic types built into C#

C# type

Size (in bytes)

.NET type

Description

byte

1

Byte

Unsigned (values between 0 and 255).

char

2

Char

Unicode characters (a modern way of storing most characters, including international language characters).

bool

1

Boolean

True or false.

sbyte

1

SByte

Signed (values between –128 and 127).

short

2

Int16

Signed (short) (values between –32,768 and 32,767).

ushort

2

UInt16

Unsigned (short) (values between 0 and 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 x 10-45 to approximately +/-3.4 x 1038 with seven significant figures.

double

8

Double

Double-precision floating-point. Holds the values from approximately +/-5.0 x 10-324 to approximately +/-1.8 x 10308 with 15 to 16 significant figures.

decimal

12

Decimal

Fixed-precision up to 28 digits and the position ...

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