# java hexadecimal to decimal – Java Program to Convert Hexadecimal to Decimal

Java hexadecimal to decimal: In the previous article, we have discussed Java Program for Decimal to Binary

## Program to convert hexadecimal to decimal

How to convert hexadecimal to decimal in java: So, before going into the program directly, let’s know about decimal and hexadecimal.

Decimal Number :

• The number system with base 10 is generally called decimal number system .
• This number system us usually consists of 10 digits i.e. 0,1,2,3,4,5,6,7,8,9
• This is the popular number system which is used in daily life .
• Example – (156)10 where “10” represents the base and “156” represents the decimal number.

• The number system with base 16 is generally called Hexadecimal number system .
• This number system us usually consists of 16 digits i.e. 0,1,2,3,4,5,6,7,8,9 and A,B,C,D,E,F
• Example – (19F)16 where “16” represents the base and “19F” represents the octal number.
• But (18H)16 will be a wrong representation because the digits are possible between 0 to 9 and A to F.

As the base is 16 so We need to multiply the digits with the base value with the power of 16 while converting it to decimal  .

Let’s take a example  say (4AB)16  is a hexadecimal number that we want to convert it to equivalent decimal then it will be as follows .

(4AB)16  = (4 × 16²) + (10 × 16¹) + (11 × 16⁰)

= 4 x 256 + 10 x 16 + 11 x 1

= 1024 + 160 +11

=(1195)10

Let’s see different ways to convert Hexadecimal to Decimal

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### Method-1: Java Program for Hexadecimal to Decimal Using inbuilt function

Approach :

• Take a hexadecimal value as the input.
• Convert it into its decimal value by using Integer.parseInt(input value , 16) Store it into a variable output .
• Print the result.

Program :

Hexadecimal to decimal java Let’s see the program to understand it more clearly.

import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
// creating scanner object
Scanner sc = new Scanner(System.in);
// input a  octal value as a string  through scanner class
System.out.println("Enter a hexadecimal  Value : ");
String input1=sc.next();
int output = Integer.parseInt(input1, 16);
System.out.println("Converted  decimal is :"+output);
}
}

Output :

Enter a hexadecimal  Value : 4AB
Converted  decimal is : 1195

### Method-2 : Java Program for Hexadecimal to Decimal Using switch case

Approach :

• Take a hexadecimal value form the input.
• Take each possible value with the help of switch case calculate its decimal equivalent of each digits.
• Add it each time and Store it into a variable lets say decimal.
• print the result.

Program :

import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
// creating scanner object
Scanner sc = new Scanner(System.in);
// input a  octal value as a string  through scanner class
System.out.println("Enter a hexadecimal  Value : ");
String input1=sc.next();
int len = input1.length() - 1;
int decimal=0;
// finding the decimal equivalent of the hexa decimal number
for(int a = 0; a < input1.length() ; a ++ )
{
char ch = input1.charAt(a);
switch (ch)
{
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
decimal = decimal + Integer.parseInt(Character.toString(ch))*
(int)Math.pow(16,len);
len--;
break;
case 'a':
case 'A':
decimal = decimal + 10 * (int)Math.pow(16,len);
len--;
break;
case 'b':
case 'B':
decimal = decimal + 11 * (int)Math.pow(16,len);
len--;
break;
case 'c':
case 'C':
decimal = decimal + 12 * (int)Math.pow(16,len);
len--;
break;
case 'd':
case 'D':
decimal = decimal + 13 * (int)Math.pow(16,len);
len--;
break;
case 'e':
case 'E':
decimal = decimal + 14 * (int)Math.pow(16,len);
len--;
break;
case 'f':
case 'F':
decimal = decimal + 15 * (int)Math.pow(16,len);
len--;
break;
default:
System.out.println("Invalid input");
break;
}
}
System.out.println("Converted  decimal is :"+decimal);
}
}


Output :

Enter a hexadecimal  Value : 4AB
Converted  decimal is : 1195

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