Chapter 4 Exercise 11, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

*4.11 (Decimal to hex) Write a program that prompts the user to enter an integer between 0 and 15 and displays its corresponding hex number. Here are some sample runs:

    
    Enter a decimal value (0 to 15): 11
    The hex value is B
    
    Enter a decimal value (0 to 15): 5
    The hex value is 5
    
    Enter a decimal value (0 to 15): 31
    31 is an invalid input

import java.util.Scanner;
 
public class ProgrammingEx4_11 {
 
 public static void main(String[] args) {
  System.out.print("Enter a decimal value (0 to 15): ");
  Scanner input = new Scanner(System.in);
  int i = input.nextInt();
 
  if (i < 0 || i > 15) {
   System.out.println(i + " is an invalid input");
   System.exit(0);
  }
 
  System.out.println("The hex value is "
    + Integer.toHexString(i).toUpperCase());
 
 }
 
}