C# | Data Types

Data types specify the type of data that a valid C# variable can hold. C# is a strongly typed programming language because in C#, each type of data (such as integer, character, float, and so forth) is predefined as part of the programming language and all constants or variables defined for a given program must be described with one of the data types.

Data types in C# is mainly divided into three categories

  • Value Data Types
  • Reference Data Types
  • Pointer Data Type
  1. Value Data Types : In C#, the Value Data Types will directly store the variable value in memory and it will also accept both signed and unsigned literals. The derived class for these data types are System.ValueType. Following are different Value Data Types in C# programming language :



    • Signed & Unsigned Integral Types : There are 8 integral types which provide support for 8-bit, 16-bit, 32-bit, and 64-bit values in signed or unsigned form.

      Alias Type Name Type Size(bits) Range Default Value
      sbyte System.Sbyte signed integer 8 -128 to 127 0
      short System.Int16 signed integer 16 -32768 to 32767 0
      Int System.Int32 signed integer 32 -231 to 231-1 0
      long System.Int64 signed integer 64 -263 to 263-1 0L
      byte System.byte unsigned integer 8 0 to 255 0
      ushort System.UInt16 unsigned integer 16 0 to 65535 0
      uint System.UInt32 unsigned integer 32 0 to 232 0
      ulong System.UInt64 unsigned integer 64 0 to 263 0
    • Floating Point Types :There are 2 floating point data types which contain the decimal point.

      • Float: It is 32-bit single-precision floating point type. It has 7 digit Precision. To initialize a float variable, use the suffix f or F. Like, float x = 3.5F;. If the suffix F or f will not use then it is treated as double.
      • Double:It is 64-bit double-precision floating point type. It has 14 – 15 digit Precision. To initialize a double variable, use the suffix d or D. But it is not mandatory to use suffix because by default floating data types are the double type.

      Alias Type name Size(bits) Range (aprox) Default Value
      float System.Single 32 3.4 × 1038 to +3.4 × 1038 0.0F
      double System.Double 64 ±5.0 × 10-324 to ±1.7 × 10308 0.0D
    • Decimal Types : The decimal type is a 128-bit data type suitable for financial and monetary calculations. It has 28-29 digit Precision. To initialize a decimal variable, use the suffix m or M. Like as, decimal x = 300.5m;. If the suffix m or M will not use then it is treated as double.

      Alias Type name Size(bits) Range (aprox) Default value
      decimal System.Decimal 128 -7.9 × 1028 to 7.9 × 1028 0.0M
    • Character Types : The character types represents a UTF-16 code unit or represents the 16-bit Unicode character.

      Alias Type name Size In(Bits) Range Default value
      char System.Char 16 U +0000 to U +ffff ‘\0’
    • Example :

      filter_none

      edit
      close

      play_arrow

      link
      brightness_4
      code

      // C# program to demonstrate 
      // the above data types
      using System;
      namespace ValueTypeTest {
            
      class GeeksforGeeks {
            
          // Main function
          static void Main()
          {
                
              // declaring character
              char a = 'G';
        
              // Integer data type is generally
              // used for numeric values
              int i = 89;
        
              short s = 56;
                
              // this will give error as number
              // is larger than short range
              // short s1 = 87878787878;
        
              // long uses Integer values which 
              // may signed or unsigned
              long l = 4564;
        
              // UInt data type is generally
              // used for unsigned integer values
              uint ui = 95;
        
              ushort us = 76;
              // this will give error as number is
              // larger than short range
        
              // ulong data type is generally
              // used for unsigned integer values
              ulong ul = 3624573;
        
              // by default fraction value
              // is double in C#
              double d = 8.358674532;
        
              // for float use 'f' as suffix
              float f = 3.7330645f;
        
              // for float use 'm' as suffix
              decimal dec = 389.5m;
        
              Console.WriteLine("char: " + a);
              Console.WriteLine("integer: " + i);
              Console.WriteLine("short: " + s);
              Console.WriteLine("long: " + l);
              Console.WriteLine("float: " + f);
              Console.WriteLine("double: " + d);
              Console.WriteLine("decimal: " + dec);
              Console.WriteLine("Unsinged integer: " + ui);
              Console.WriteLine("Unsinged short: " + us);
              Console.WriteLine("Unsinged long: " + ul);
          }
      }
      }

      chevron_right

      
      

      Output :

      char: G
      integer: 89
      short: 56
      long: 4564
      float: 3.733064
      double: 8.358674532
      decimal: 389.5
      Unsinged integer: 95
      Unsinged short: 76
      Unsinged long: 3624573
      

      Example :

      filter_none

      edit
      close

      play_arrow

      link
      brightness_4
      code

      // C# program to demonstrate the Sbyte
      // signed integral data type
      using System;
      namespace ValueTypeTest {
        
      class GeeksforGeeks {
        
          // Main function
          static void Main()
          {
              sbyte a = 126;
        
              // sbyte is 8 bit 
              // singned value
              Console.WriteLine(a);
        
              a++;
              Console.WriteLine(a);
        
              // It overflows here because
              // byte can hold values 
              // from -128 to 127
              a++;
              Console.WriteLine(a);
        
              // Looping back within 
              // the range
              a++;
              Console.WriteLine(a);
          }
      }
      }

      chevron_right

      
      

      Output :

      126
      127
      -128
      -127
      

      Example :


      filter_none

      edit
      close

      play_arrow

      link
      brightness_4
      code

      // C# program to demonstrate 
      // the byte data type
      using System;
      namespace ValueTypeTest {
        
      class GeeksforGeeks {
            
          // Main function
          static void Main()
          {
              byte a = 0;
        
              // byte is 8 bit 
              // unsigned value
              Console.WriteLine(a);
        
              a++;
              Console.WriteLine(a);
        
              a = 254;
                
              // It overflows here because
              // byte can hold values from
              // 0 to 255
              a++;
              Console.WriteLine(a);
        
              // Looping back within the range
              a++;
              Console.WriteLine(a);
          }
      }
      }

      chevron_right

      
      

      Output :

      0
      1
      255
      0
      
    • Boolean Types : It has to be assigned either true or false value. Values of type bool are not converted implicitly or explicitly (with casts) to any other type. But the programmer can easily write conversion code.

      Alias Type name Values
      bool System.Boolean True / False

      Example :

      filter_none

      edit
      close

      play_arrow

      link
      brightness_4
      code

      // C# program to demonstrate the
      // boolean data type
      using System;
      namespace ValueTypeTest {
            
          class GeeksforGeeks {
                
          // Main function
          static void Main() 
          {
                
              // boolean data type
              bool b = true;     
              if (b == true)
                  Console.WriteLine("Hi Geek");
          
      }
      }

      chevron_right

      
      

      Output :

      Hi Geek
      
  2. Reference Data Types : The Reference Data Types will contain a memory address of variable value because the reference types won’t store the variable value directly in memory. The built-in reference types are string, object.
    • String : It represents a sequence of Unicode characters and its type name is System.String. So, string and String are equivalent.
      Example :

      string s1 = "hello"; // creating through string keyword  
      String s2 = "welcome"; // creating through String class  
      
    • Object : In C#, all types, predefined and user-defined, reference types and value types, inherit directly or indirectly from Object. So basically it is the base class for all the data types in C#. Before assigning values, it needs type conversion. When a variable of a value type is converted to object, it’s called boxing. When a variable of type object is converted to a value type, it’s called unboxing. Its type name is System.Object.
    • Example :

      filter_none

      edit
      close

      play_arrow

      link
      brightness_4
      code

      // C# program to demonstrate 
      // the Reference data types
      using System;
      namespace ValueTypeTest {
            
      class GeeksforGeeks {
            
          // Main Function
          static void Main() 
          {
                
              // declaring string
              string a = "Geeks"
                
              //append in a
              a+="for";
              a = a+"Geeks"
              Console.WriteLine(a);
                
              // declare object obj
              object obj;
              obj = 20;
              Console.WriteLine(obj);
                
              // to show type of object
              // using GetType()
              Console.WriteLine(obj.GetType()); 
          
      }
      }

      chevron_right

      
      

      Output :

      GeeksforGeeks
      20
      System.Int32
      
  3. Pointer Data Type : The Pointer Data Types will contain a memory address of the variable value.
    To get the pointer details we have a two symbols ampersand (&) and asterisk (*).
    ampersand (&): It is Known as Address Operator. It is used to determine the address of a variable.
    asterisk (*): It also known as Indirection Operator. It is used to access the value of an address.
    Syntax :

    type* identifier;
    

    Example :

    int* p1, p;   // Valid syntax
    int *p1, *p;   // Invalid 
    

    Example :

    filter_none

    edit
    close

    play_arrow

    link
    brightness_4
    code

    // Note: This program will not work on
    // online compiler
    // Error: Unsafe code requires the `unsafe' 
    // command line option to be specified
    // For its solution:
    // Go to your project properties page and
    // check under Build the checkbox Allow
    // unsafe code.
    using System;
    namespace Pointerprogram {
          
    class GFG {
      
        // Main function
        static void Main()
        {
            unsafe
            {
                  
                // declare variable
                int n = 10;
                  
                // store variable n address 
                // location in pointer variable p
                int* p = &n;
                Console.WriteLine("Value :{0}", n);
                Console.WriteLine("Address :{0}", (int)p);
            }
        }
    }
    }

    chevron_right

    
    



My Personal Notes arrow_drop_up

This article is contributed by Mithun Kumar & jit_t. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.



Improved By : AlokSingh9