C# | Literals

The fixed values are called as Literal. Literal is a value that is used by the variables. Values can be either an integer, float or string, etc. 

// Here 100 is a constant/literal.
int x = 100; 

Literals can be of the following types: 

• Integer Literals
• Floating-point Literals
• Character Literals
• String Literals
• Null Literals
• Boolean Literals

Integer Literals: A literal of integer type is known as the integer literal. It can be octal, decimal, binary, or hexadecimal constant. No prefix is required for the decimal numbers. A suffix can also be used with the integer literals like U or u are used for unsigned numbers while l or L are used for long numbers. By default, every literal is of int type. For Integral data types (byte, short, int, long), we can specify literals in the ways:

• Decimal literals (Base 10): In this form, the allowed digits are 0-9.

int x = 101;

• Octal literals (Base 8): In this form, the allowed digits are 0-7.

// The octal number should be prefix with 0.
int x = 0146; 

• Hexa-decimal literals (Base 16): In this form, the allowed digits are 0-9 and characters are a-f. We can use both uppercase and lowercase characters. As we know that c# is a case-sensitive programming language but here c# is not case-sensitive.

// The hexa-decimal number should be prefix
// with 0X or 0x.
int x = 0X123Face; 

• Binary literals (Base 2): In this form, the allowed digits are only 1’s and 0’s.

// The binary number should be prefix with 0b.
int x = 0b101

Examples:

07778    // invalid: 8 is not an octal digit 
045uu    // invalid: suffix (u) is repeated
0b105    // invalid: 5 is not a binary digit
0b101    // valid binary literal
456      // valid decimal literal
02453    // valid octal literal 
0x65d    // valid hexadecimal literal 
12356    // valid int literal 
304U     // valid unsigned int literal 
3078L    // valid long literal 
965UL    // valid unsigned long literal 

Program:

C#

// C# program to illustrate the use of Integer Literals
using System;

class Geeks{

    // Main method
    public static void Main(String[] args)
    {

        // decimal-form literal
        int a = 101;

        // octal-form literal
        int b = 0145;

        // Hexa-decimal form literal
        int c = 0xFace;

        // binary-form literal
        int x = 0b101;

        Console.WriteLine(a);
        Console.WriteLine(b);
        Console.WriteLine(c);
        Console.WriteLine(x);
    }
}

101
145
64206
5

Floating-point Literals: The literal which has an integer part, a decimal point, a fractional part, and an exponent part is known as the floating-point literal. These can be represented either in decimal form or exponential form.

Examples:

Double d = 3.14145       // Valid
Double d = 312569E-5      // Valid
Double d = 125E             // invalid: Incomplete exponent 
Double d = 784f            // valid
Double d = .e45           // invalid: missing integer or fraction

Program:

C#

// C# program to illustrate the use of
// floating-point literals
using System;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {
        // decimal-form literal
        double a = 101.230;

        // It also acts as decimal literal
        double b = 0123.222;

        Console.WriteLine(a);
        Console.WriteLine(b);
    }
}

Output:

101.23
123.222

Note: By default, every floating-point literal is of double type and hence we can’t assign directly to float variable. But we can specify floating-point literal as float type by suffixed with f or F. We can specify explicitly floating-point literal as the double type by suffixed with d or D, of course, this convention is not required.

Character Literals: For character data types we can specify literals in 3 ways: 

• Single quote: We can specify literal to char data type as single character within single quote.

char ch = 'a';

• Unicode Representation: We can specify char literals in Unicode representation ‘\uxxxx’. Here xxxx represents 4 hexadecimal numbers.

char ch = '\u0061';// Here /u0061 represent a.

• Escape Sequence: Every escape character can be specified as char literals.

char ch = '\n';

Escape Sequence	Meaning
\\	\ character
\’	‘ character
\?	? character
\”	” character
\b	Backspace
\a	Alert or Bell
\n	New Line
\f	Form Feed
\r	Carriage Return
\v	Vertical Tab
\xhh…	Hexadecimal number of one or more digits

Example :

C#

// C# program to illustrate the use of char literals
using System;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        // character literal within single quote
        char ch = 'a';

        // Unicode representation
        char c = '\u0061';

        Console.WriteLine(ch);
        Console.WriteLine(c);

        // Escape character literal
        Console.WriteLine("Hello\n\nGeeks\t!");
    }
}

a
a
Hello

Geeks    !

String Literals: Literals which are enclosed in double quotes(“”) or starts with @”” are known as the String literals. 

Examples:

String s1 = "Hello Geeks!";

String s2 = @"Hello Geeks!";

Program:

C#

// C#  program to illustrate the use of String literals
using System;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        String s = "Hello Geeks!";
        String s2 = @"Hello Geeks!";

        // If we assign without "" then it
        // treats as a variable
        // and causes compiler error
        // String s1 = Geeks;

        Console.WriteLine(s);
        Console.WriteLine(s2);
    }
}

Output:

Hello Geeks!
Hello Geeks!

Boolean Literals: Only two values are allowed for Boolean literals i.e. true and false.

Example:

bool b = true;
bool c = false;

Program:

C#

// C# program to illustrate the use
// of boolean literals
using System;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {
        bool b = true;
        bool c = false;

        // these will give compile time error
        // bool d = 0;
        // bool e = 1;
        // Console.WriteLine(d);
        // Console.WriteLine(e);

        Console.WriteLine(b);
        Console.WriteLine(c);
    }
}

Output:

True
False