Convert any base number to decimal

Question

Is there a way to convert any number of base 2-16 into decimal?
The numbers can be input using scanner
Anyone has any code for this?

Answer 1

Hey, guys this is what I got so far for this. But, of course there are issues
1. I'm not sure how to show "invalid" message if a character or floating point number is entered
2. I'm not sure about the code that will only allow the relevant numbers to be entered for each base.
E.g - If base = 2 then number == 1 || 0
This has to be repeated for all allowed base from 2-16
Please help!!!
import java.util.Scanner;
public class BaseConverter {
public static void main(String[] args) {
int base;
String number;
Scanner scanner = new Scanner(System.in);
System.out.print("Enter base value (Integer between 2 to 16): ");
base = scanner.nextInt();
if (base < 2 || base > 16) {                     // how to get same invalid message for character or float (e.g. -12.2)
System.out.println("Invalid base. Please retry");
return;
System.out.print("Enter the number in base : ");
number = scanner.next();
if (scanner.hasNext()) {           // not sure how to validate in relation to entered base
} else {
System.out.println("Invalid number. Please retry");
return;
int decimalValue = 0;
int step = 0;
for (int i = number.length() - 1; i >= 0; i--) {
char c = number.charAt(i);
int cValue = Character.digit(c, base);
decimalValue = decimalValue + (cValue * (int) Math.pow(base, step));
step = step + 1;
System.out.println("Decimal value: " + decimalValue);
}