C# Program to write a number in hexadecimal format

Converting numbers to hexadecimal format in C# can be accomplished using various format specifiers. Hexadecimal is a base-16 number system commonly used in programming for representing binary data in a more readable format.

Syntax

Following are the main hexadecimal format specifiers in C# −

{0:x}    // lowercase hexadecimal
{0:X}    // uppercase hexadecimal
{0:x8}   // lowercase with 8 digits (zero-padded)
{0:X8}   // uppercase with 8 digits (zero-padded)

You can also use the ToString() method with format specifiers −

number.ToString("x")    // lowercase hexadecimal
number.ToString("X")    // uppercase hexadecimal
number.ToString("x8")   // lowercase with padding

Using Format Specifiers with Console.WriteLine

The most common approach is using format specifiers with Console.WriteLine −

using System;

class Demo {
   static void Main() {
      int a = 12250;
      Console.WriteLine("Original number: " + a);
      Console.WriteLine("Lowercase hex: {0:x}", a);
      Console.WriteLine("Lowercase hex (8 digits): {0:x8}", a);
      Console.WriteLine("Uppercase hex: {0:X}", a);
      Console.WriteLine("Uppercase hex (8 digits): {0:X8}", a);
   }
}

The output of the above code is −

Original number: 12250
Lowercase hex: 2fda
Lowercase hex (8 digits): 00002fda
Uppercase hex: 2FDA
Uppercase hex (8 digits): 00002FDA

Using ToString() Method

Another approach is using the ToString() method with hexadecimal format strings −

using System;

class HexExample {
   static void Main() {
      int number = 255;
      Console.WriteLine("Number: " + number);
      Console.WriteLine("Hex (lowercase): " + number.ToString("x"));
      Console.WriteLine("Hex (uppercase): " + number.ToString("X"));
      Console.WriteLine("Hex (4 digits): " + number.ToString("x4"));
      Console.WriteLine("Hex (uppercase, 4 digits): " + number.ToString("X4"));
   }
}

The output of the above code is −

Number: 255
Hex (lowercase): ff
Hex (uppercase): FF
Hex (4 digits): 00ff
Hex (uppercase, 4 digits): 00FF

Converting Different Data Types

You can convert various integer data types to hexadecimal format −

using System;

class MultiTypeHex {
   static void Main() {
      byte byteValue = 200;
      short shortValue = 4096;
      long longValue = 1000000;
      
      Console.WriteLine("Byte to hex: " + byteValue.ToString("X2"));
      Console.WriteLine("Short to hex: " + shortValue.ToString("X4"));
      Console.WriteLine("Long to hex: " + longValue.ToString("X"));
      
      Console.WriteLine("Using format specifiers:");
      Console.WriteLine("Byte: {0:X2}", byteValue);
      Console.WriteLine("Short: {0:X4}", shortValue);
      Console.WriteLine("Long: {0:X}", longValue);
   }
}

The output of the above code is −

Byte to hex: C8
Short to hex: 1000
Long to hex: F4240
Using format specifiers:
Byte: C8
Short: 1000
Long: F4240

Format Specifier Comparison

Conclusion

C# provides flexible options for converting numbers to hexadecimal format using format specifiers like {0:x}, {0:X} with Console.WriteLine, or the ToString() method with format strings. The digit padding option allows consistent formatting for display purposes.