# Java Program to illustrate the Usage of HexaDecimal

• Last Updated : 06 Jun, 2021

A decimal number is the sum of digits multiplied with a power of 10. Decimal numbers are represented with base 10 whereas hexadecimal Number is the sum of digits multiplied with the power of 16, somehow there are similar traits in the internal working of them just they are two different ways to present a number. The hexadecimal system has 16 different digit symbols. Different numbers can be generated using the combination of digits from 0 to 15. The representation in the hexadecimal system is the same as the decimal number system from 0 to 9 but then onwards it changes.

Representation:

0      —>      0

:   :

9      —>      9

10      —>      A

11      —>      B

12      —>      C

13      —>      D

14      —>      E

15      —>      F

Illustration: Internal Working

```A. Decimal to Hexadecimal Number System

(1) (13)10 --> (D)16
Directly can be writen 13 as D in hexadecimal system

(2) (16)10 ---> (10)16
( 16 )16 = ( 1 x 161) + ( 0 * 160)

(3) (59)10 ---> (3B)16
( 59 )10 --> ( 3 * 161) + (11 * 160)```

Conclusion:

`For a Decimal Number system-> ( 421 )10 = (4 x 102) + (2 x 101) + (1 x 100)`
```B. Similarly ,Hexadecimal to Decimal Number System
(8A)16 ---> (138)10
(8A)16 --> (8 x 161) + (10 x 160)```

Conclusion:

`In Java programs, hexadecimal numbers are written by placing 0x before numbers.`

Below are 4 examples been discusses to illustrate the usage of Hexadecimal Number

1. Converting Hex number to Decimal number
2. Converting Decimal number to Hex number
3. Converting Hex number to Long number
4. Converting Long number to Hex number

Example 1: Java program to convert Hex number to Decimal number

## Java

 `// Java program to convert Hex number to Decimal number` `// Importing input/output java library``import` `java.io.*;` `class` `GFG {` `    ``// Main driver method``    ``public` `static` `void` `main(String[] args)``    ``{` `        ``// Hexadecimal number stored in a string``        ``String hexNum = ``"100"``;` `        ``/* Random hexadecimal number */` `        ``// Passing hexnum and base as parameters``        ``// which is 16 to parseInt function``        ``int` `decimal = Integer.parseInt(hexNum, ``16``);` `        ``// Printing the output result as``        ``// decimal equivalent of hexa-decimal``        ``System.out.println(``"Decimal value is "` `+ decimal);``    ``}``}`

Output
`Decimal value is 256`

Example 2: Java program to convert Decimal number to Hex number

## Java

 `// Java Program to Illustrate the Usage of HexaDecimal` `// Importing input/output java library``import` `java.io.*;` `class` `GFG {` `    ``// Main driver function``    ``public` `static` `void` `main(String[] args)``    ``{` `        ``/* Decimal number to be converted */``        ``int` `i = ``257``;` `        ``// Using toHexString() method for getting decNum and``        ``// Storing the hexaDecNum in a string``        ``String hex = Integer.toHexString(i);` `        ``// Printing hexaDecNum of decNum``        ``System.out.println(``"Hex value is "` `+ hex);``    ``}``}`

Output
`Hex value is 101`

Example 3: Java program to convert Hex number to Long number

## Java

 `// Java Program to Illustrate the Usage of HexaDecimal` `// Importing input/output java library``import` `java.io.*;` `class` `GFG {` `    ``// Main driver method``    ``public` `static` `void` `main(String[] args)``    ``{` `        ``// Hexadecimal number stored in a string``        ``String hexNum = ``"10000"``;` `        ``// passing hexnum and base as parameters``        ``// which is 16 to parseLong function``        ``long` `num = Long.parseLong(hexNum, ``16``);` `        ``// Printing long value of HexaDecNum``        ``System.out.println(``"Long value is "` `+ num);``    ``}``}`

Output
`Long value is 65536`

Example 4: Java program to convert Long number to Hex number

## Java

 `// Java Program to Illustrate the Usage of HexaDecimal` `// Importing java input/output library``import` `java.io.*;` `class` `GFG {` `    ``// Main driver function``    ``public` `static` `void` `main(String[] args)``    ``{` `        ``/* Long number to be converted */``        ``long` `i = ``1024``;` `        ``// Storing the result in a string``        ``String hex = Long.toHexString(i);` `        ``// Displaying Result``        ``System.out.println(``"Hex value is "` `+ hex);``    ``}``}`

Output
`Hex value is 400`

Note: There are two more conventions for hexadecimal numbers, 400h or \$400. They both are the same as 0x400.

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