Answer:
//import the Scanner class to allow for user's inputs
import java.util.Scanner;
//Declaration of class lab5
public class lab5 {
public static void main(String[] args) {
//Create an object of the Scanner class to allow for user's input
//Call the object input
Scanner input = new Scanner(System.in);
//Declare int variable to hold the user's number
int number;
//Create an infinite while loop to keep asking
// the user to re-enter the number if the number is not within range
while (true) {
//Prompt the user to enter a number within the range.
System.out.println("Please enter a number between 100 and 10,000");
//Receive the number from the user and
//store in the integer variable called number
number = input.nextInt();
// Check if the number is within range.
// If it is, then break out of the loop
// Otherwise, repeat the loop
if (number > 100 && number < 10000) {
break;
}
} // End of while loop
//For simplicity, first convert the number to a string
//by concatenating it with an empty space as follows
String num = number + "";
//Display a message describing the result
System.out.println("The number in reverse is : ")
//Now, print each character in the string in reverse order
//using a for loop as follows
for (int i = num.length() - 1; i >= 0; i--) {
System.out.print(num.charAt(i));
}
} // End of main method
} // End of class declaration
===============================================================
Sample Output 1:
>> Please enter a number between 100 and 10,000
2
>> Please enter a number between 100 and 10,000
8000078
>> Please enter a number between 100 and 10,000
900
>> The number in reverse is :
009
=================================================================
=================================================================
Sample Output 2
>> Please enter a number between 100 and 10,000
256
>> The number in reverse is :
625
=================================================================
Step-by-step explanation:
The code above contains comments explaining every part of the code. Please go through these comments.
For simplicity and clarification, the code is re-written as follows without comments;
===================================================
import java.util.Scanner;
public class lab5 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int number;
while (true) {
System.out.println("Please enter a number between 100 and 10,000");
number = input.nextInt();
if (number > 100 && number < 10000) {
break;
}
}
String num = number + "";
System.out.println("The number in reverse is : ")
for (int i = num.length() - 1; i >= 0; i--) {
System.out.print(num.charAt(i));
}
}
}
============================================================