Chapter 5, Problem 19E

Explanation of Solution

Program:

//definition of "Main" class

class Main

{

    //definition of main method

    public static void main(String[] args)

    {

        //call the method and display the output

System.out.println("The first digit is: " + firstDigit(3572));

    }

    //definition of "firstDigit" method

    public static int firstDigit(int num)

    {

        //check "num" is less than 0

        if (num < 0)

        {

            //calculate "num" value

            num = num * -1;

        }

        //check "num" g...