Cs Value Types

C#’s Value Types

C# contains two general categories of built-in data types: value types and reference types. C#’s reference types are defined by classes, and a discussion of classes is deferred until later. However, at the core of C# are its 13 value types, which are shown in Table 3-1. These are built-in types that are defined by keywords in the C# language, and they are available for use by any C# program.

Table 3-1: The C# Value Types

Type	Meaning
bool	Represents true/false values
byte	8-bit unsigned integer
char	Character
decimal	Numeric type for financial calculations
double	Double-precision floating point
float	Single-precision floating point
int	Integer
long	Long integer
sbyte	8-bit signed integer
short	Short integer
uint	An unsigned integer
ulong	An unsigned long integer
ushort	An unsigned short integer

The term value type indicates that variables of these types contain their values directly. (This differs from reference types, in which a variable contains a reference to the actual value.) Thus, the value types act much like the data types found in other programming languages, such as C++. The value types are also known as simple types. The term primitive type is also occasionally used.

C# strictly specifies a range and behavior for each value type. Because of portability requirements, C# is uncompromising on this account. For example, an int is the same in all execution environments. There is no need to rewrite code to fit a specific platform. While strictly specifying the size of the value types may cause a small loss of performance in some environments, it is necessary in order to achieve portability.

Note 

C# 2.0 added a new feature called a nullable type, which enables a variable to hold an undefined value. A nullable type can be created for any value type, including the built-in types. Nullable types are discussed in Chapter 19.