What is DataType?
A data type in a programming language is a set of data with values having predefined characteristics. It describes how the value will be stored for the type and how it will be processed.
DataTypes in c#:
The C# programming language is a strongly typed language. All variables must be declared with a valid data type.
Types of DataTypes:
There are two types of datatype:
1. Built In data type
2. User Defined data type
Built In data type:
The built in data types are provided by the c# .NET frameword. The data types are reserved keywords and cannot be used as a variable name.
Built in data types supported in c# are:
byte - 0 to 255 characters
sbyte(short byte) - (-128 to 127)
short - 32,768 to 32,767
ushort(unsigned short) - 0 to 65,535
int -2,147,483,648 to 2,147,483,647
uint(unsigned int) 0 to 4,294,967,295
long -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
ulong 0 to 18,446,744,073,709,551,615
float - (-3.402823e38 to 3.402823e38 )
double - ( -1.79769313486232e308 to 1.79769313486232e308 )
decimal ( -79228162514264337593543950335 to 79228162514264337593543950335 )
char - A Unicode character.
string - A string of Unicode characters.
bool - True or False.
object - An object.
User Defined data type
The user defined data type, will be defined by the user.
Class or Interface
Enumerations - user defined integer type
The data types can further be classified into
a) Value Types
b) Reference Types
The value type variables store the actual data in the variable. Each variable maintains its own copy of data.
int x = 10;
double y = 10.12;
char z = 's';
The following value types are supported in c#:
Reference types variables store the reference of the actual data.
The following reference types are supported in c#.
* string - represents a string of unicode characters.
* object - Represents a general purpose type. In C#, all predefined and user-defined types inherit from the object type or System.Object class.
string s = "TestString";
Although string is a reference type, the equality operators (== and !=) are defined to compare the values of string objects, not references.
public delegate void TestDelegate(string message);
The delegate keyword is used to declare a reference type that can be used to encapsulate a named or an anonymous method
Data Type Conversions:
C# supports two types of conversions.
1. Implicit conversions
2. Explicit conversions.
Implicit conversions are direct conversion. It includes method invoking and assignment.
int iVal = 34;
long lVal = intValue;
Explicit conversions includes type casting. By using a cast expression for conversion.
long lVal = 123456;
int iVal = (int) lVal;
What is DataType?