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 3 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

1.1 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.

1.2 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.

1.3 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.

1.4 Character Types

The character types represents a UTF-16 code unit or represents the 16-bit Unicode character.

Example 1:

// 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);
    }
}
}

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 2:

// 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);
    }
}
}

126
127
-128
-127

Example 3:

// 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);
    }
}
}

0
1
255
0

1.5 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.

Example:

// Using 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");
    }
}
}

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. When you create a reference type variable, such as an object or a string, you are actually storing a reference (or pointer) to the location in memory where the data is held. The actual data for reference types is stored on the heap. The heap is a large pool of memory used for dynamic memory allocation. The built-in reference types are string, object.

2.1 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  

2.2 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:

// Using Reference data types
using System;

namespace ValueTypeTest {

class Geeks {
    
    // 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()); 
    } 
}
}

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:

// Valid syntax 
int* p1, p;   

// Invalid
int *p1, *p;   

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.

Implementation:

// Using Pointer Data Type
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);
        }
    }
}
}

Output:

Value :10
Address :1988374520