Java – applet – how do I use this code using strings instead of characters?

I'm slowly trying to write a program that converts hexadecimal numbers to decimal numbers I'm not interested in reading the completed, well-known code because I want to do it myself I have an idea, but something interferes with me

import java.util.Scanner;
public class Test{
    public static void main(String[] args){
        Scanner input = new Scanner(system.in);
        String any = input.nextLine();
        char[] cArray = any.tocharArray();
        for(int i=0; i<cArray.length; i++){
            System.out.print(cArray[i]+" ");
        }
    }
}

Input: ab12
Output: a b 1 2

I want to replace a with 10, B with 11, C with 12, etc

If I add an IF statement to the for loop, it works

for(int i=0; i<cArray.length; i++){
            if(cArray[i] == 'a'){
               cArray[i] = '10'; // doesn't work,read below
            }
            System.out.print(cArray[i]+" ");
        }

The problem is that I want to replace 10 and 10 is no longer a character because it consists of two letters That's why I want to know how to use strings instead of characters to use this code?

Solution

hint

'a' - 87 = 10

So you can use:

(int) cArray[i] - 87

Because:

(int)'a' = 97

I hope you understand the idea