Java Program To Convert Decimal To Hexadecimal

To convert a decimal number to a hexadecimal number, use the following algorithm.

toHex(x)

1. let S be the stack
2. q = x / 16 and r = x % 16 // where q and r are the quotient and
   remainder
3. S.push(q) if q > 0 
4. S.push(r) 
5. while (top element e > 15)
   • pop out top element e
   • q = e / 16
   • r = e % 16
   • S.push(q)
   • S.push(r)
6. let C is the char list
7. while (stack is not empty)
   • e = pop out top element
   • if e is lie between 10 to 15 replace it with its corresponding hex digit
   • C.append(e)
8. return C.toString()

public class Main {

 public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int decimal = scan.nextInt();
        System.out.println(toHex(decimal));
 }



     /**
     * Convert To Hex
     */
    public static String toHex(final int X) {
        final Stack<Integer> S = new Stack<>();
        int q = X / 16;
        int r = X % 16;

        S.push(r);
        if (q > 0) S.push(q);


        while (S.peek() > 15) {
            int e = S.pop();
            q = e / 16;
            r = e % 16;

            S.push(r);
            S.push(q);
        }

        StringBuilder C = new StringBuilder();
        while (!S.isEmpty()) {
            int e = S.pop();
            switch (e) {
                case 10 -> C.append('A');
                case 11 -> C.append('B');
                case 12 -> C.append('C');
                case 13 -> C.append('D');
                case 14 -> C.append('E');
                case 15 -> C.append('F');
                default -> C.append(e);
            }
        }

        return C.toString();
    }
}