Let’s learn java convert hex to decimal.
Java convert hex to decimal
Java program that converts a hexadecimal number to a decimal number is one of the frequently asked java program interview question.
In hexadecimal to decimal java conversion we are using Integer.parseInt() method.
Integer.parseInt() method parses string argument as a signed integer in the radix specified by the second argument.
Here’s the syntax.
public static int parseInt(String s, int radix) throws NumberFormatException
Let’s see java program.
public class ConvertHexToDecimal { public static void main(String[] args) { String strHex = "b"; int decimal = Integer.parseInt(strHex, 16); System.out.println("Decimal number : " + decimal); } }
Output:
Decimal number : 11
Hexadecimal to decimal java user input
Meanwhile to we can convert hexadecimal to decimal based on user input. For this we need Scanner class.
Logic to convert a hexadecimal to a decimal number is same as above java program.
Now let’s see hexadecimal to decimal java user input.
import java.util.Scanner; public class HexToDecimalDemo { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Please enter hexadecimal number: "); String strHexNumber = sc.nextLine(); // converting hexadecimal to decimal by passing base 16 int decimalNumber = Integer.parseInt(strHexNumber, 16); System.out.println("Converting hexadecimal to decimal: " + decimalNumber); sc.close(); } }
Output:
Please enter hexadecimal number: 6A
Converting hexadecimal to decimal: 106
Similarly we can convert hexadecimal to decimal java using user defined method.
public class HexaToDecimal { public static int convertHexadecimal(String strHex) { String Hexadecimal = "0123456789ABCDEF"; strHex = strHex.toUpperCase(); int value = 0; for(int a = 0; a < strHex.length(); a++) { char ch = strHex.charAt(a); int d = Hexadecimal.indexOf(ch); value = 16 * value + d; } return value; } public static void main(String[] args) { System.out.println("Decimal value of b is : " + convertHexadecimal("b")); System.out.println("Decimal value of d is : " + convertHexadecimal("d")); System.out.println("Decimal value of 151 is : " + convertHexadecimal("151")); } }
Output:

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