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Data Types In C#

It is important to classify data into various types (like numeric, character, decimals etc.). In real world people use various types of data depends upon the requirements. For example a chartered accountant or a salesman uses numeric data more frequently as compared to an English teacher or an English teacher uses English characters more frequently as compared to a salesman or a chartered accountant.

In programming language as well data is also categorized to cater the need of various people or in other words we can say that a programming language supports various data types.

In this article we will discuss about various data types that C# supports. Along with that I will also specify the default value of each data type. Default value in programming language is a predesigned value used by a computer program when a value is not specified the programmer.

Signed And Unsigned Numbers

There are data types in C# (or other programming language as well) that are both signed and unsigned like int, long, short and byte.

Signed numbers are those numbers that represents positive and negative number whereas unsigned represents zero or positive numbers.

C# supports following data types.

Boolean

Boolean data type has 2 possible values i.e. true or false. Default value is false. Boolean variable can be declared as

Boolean x = false;
bool y = false;

Byte And Sbyte

In computers, information is stored in the form of bit.
A bit is the smallest unit of information.
A bit is a single numeric value that is either ‘0’ or ‘1’.

For example the number 2 is represented as 00000010.

Let’s talk about bytes now

A Byte is a sequence of bits.
8 bits makes 1 byte.

As specified 8 bits makes 1 byte and each but contains either ‘0’ or ‘1’, so the minimum value of a byte is 00000000 and maximum value is 11111111.

If you convert the minimum and maximum value into numbers then the minimum value will be zero and maximum value will be 255. If you want to understand how they are converted from bit to numbers then I suggest you to search for ‘bit to decimal converter’.

So the summary is

Data Type	Minimum Value	Maximum Value
byte	0	255
sbyte	-128	127

In C# byte is declared as

byte unsignedByte = 240;
sbyte signedByte = -120;

Char

Before we learn about char data type let us first start with basics.

A character is the basic unit of any language. For example ‘A’ is a character of English language. All the allowable characters of a language (for example a-z and A-Z in English) forms a character set.

But a computer never understand the character of any language, whether it is English, Hindi or Chinese. So each character is assigned a unique number (code point) that a computer can understand. This is called encoding.

There is a requirement for a standard and unified character encoding that can encode all the characters of all the languages as well all the special symbols you can think of. Here is when Unicode come into the picture.

So a Unicode assign a number to all the characters of all the languages. Each number is represented by one or more byte. If a character is represented by a single byte then we call it as 8-bit Unicode character.

So a char is a 16-bit Unicode character. A char variable is declared as

char x = 'A'; // Single character
char y = '\u0041'; // Unicode of 'A'

In the preceding code both variables ‘x’ and ‘y’ is having the same value i.e. ‘A’. So a char variable can be represented by a single character or by Unicode. In the preceding code ‘\u’ represents Unicode.

Data Type	Minimum Value	Maximum Value
char	'\u0000'	'\uffff'

Before we go to another data type I suggest you to check for all 16-bit Unicode characters.

Int, Long, Short, Uint, Ulong And Ushort

All of these data types represent numeric values but the difference is with the size.

Data Type	Minimum Value	Maximum Value
int	-2,147,483,648	2,147,483,647
long	-923,372,036,854,775,808	9,223,372,036,854,775,807
short	-32,768	32,767
uint	0	4,294,967,295
ulong	0	18,446,744,073,709,551,615
ushort	0	65535

int a;
long b;
short c;
uint d;
ulong e;
ushort f;

Decimal, Double And Float

All the three data types represent floating point. But the difference is the precision. Following table highlights the difference among these three data types.

Data Type	Size	Precision
float	32-bit	7 significant digits
double	64-bit	15-16 significant digits
decimal	128-bit	28-29 significant digits

Significant digits are all the digits in a number. But there are certain rules

All non-zero digits are significant digits.
Zero among the non-zero digits is significant digits.
All leading zeros before decimal are non-significant.
All zeros after decimal are significant digits.

For example-

12 contain 2 significant digits.
7000 contain 1 significant digit
4009 contain 4 significant digits.
4.20 contain 3 significant digits.

decimal a = 0.0M;
float b = 0.0F;
double c = 0.0;

Posted By -	Karan Gupta

Posted On -	Tuesday, May 5, 2015

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