Programa Java para conversión hexadecimal a decimal

Java

// Java program to convert Hexadecimal to Decimal Number
  
// Importing input output classes
import java.io.*;
  
// Main class
class GFG {
  
    // Method
    // To convert hexadecimal to decimal
    static int hexadecimalToDecimal(String hexVal)
    {
        // Storing the length of the
        int len = hexVal.length();
  
        // Initializing base value to 1, i.e 16^0
        int base = 1;
  
        // Initially declaring and initializing
        // decimal value to zero
        int dec_val = 0;
  
        // Extracting characters as
        // digits from last character
  
        for (int i = len - 1; i >= 0; i--) {
  
            // Condition check
            // Case 1
            // If character lies in '0'-'9', converting
            // it to integral 0-9 by subtracting 48 from
            // ASCII value
            if (hexVal.charAt(i) >= '0'
                && hexVal.charAt(i) <= '9') {
                dec_val += (hexVal.charAt(i) - 48) * base;
  
                // Incrementing base by power
                base = base * 16;
            }
  
            // Case 2
            // if case 1 is bypassed
  
            // Now, if character lies in 'A'-'F' ,
            // converting it to integral 10 - 15 by
            // subtracting 55 from ASCII value
            else if (hexVal.charAt(i) >= 'A'
                     && hexVal.charAt(i) <= 'F') {
                dec_val += (hexVal.charAt(i) - 55) * base;
  
                // Incrementing base by power
                base = base * 16;
            }
        }
  
        // Returning the decimal value
        return dec_val;
    }
  
    // Method 2
    // Main driver method
    public static void main(String[] args)
    {
        // Custom input hexadecimal number to be
        // converted into decimal number
        String hexNum = "1A";
  
        // Calling the above method to convert and
        // alongside printing the hexadecimal number
        System.out.println(hexadecimalToDecimal(hexNum));
    }
}