Java Program to Print Natural Numbers in Reverse

Write a Java Program to Print Natural Numbers in Reverse using For Loop, and While Loop with example.

Java Program to Print Natural Numbers in Reverse Example 1

This program allows the user to enter any integer value (the maximum limit value). Next, it will print all the natural numbers from maximum limit value to 1 using For Loop.

// Java Program to Print Natural Numbers in Reverse 
import java.util.Scanner;

public class ReverseNaturalNum1 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int number, i;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the Maximum integer Value : ");
		number = sc.nextInt();	
		
		for(i = number; i >= 1; i--)
		{
			System.out.print(i +"\t"); 
		}	
	}
}

OUTPUT

ANALYSIS

First we used the For loop to iterate from maximum value (Here, number = 5) to 1.

User entered value: number  = 5

For Loop First Iteration: for(i = 5; i >= 1; i–)
Condition is True. So, i Value will be printed (i.e., 5)

Second Iteration: for(i = 4; 4 >= 1; 4–)
Condition is True. So, 4 is printed

Third Iteration: for(i = 3; 3 >= 1; 3–)
Condition is True. 3 is printed

Fourth Iteration: for(i = 2; 2 >= 1; 2–)
Condition is True. 2 is printed

Fifth Iteration: for(i = 1; 1 >= 1; 1–)
Condition is True. 1 is printed

Sixth Iteration: for(i = 0; 0 >= 1; 0–)
Condition (0 >= 1) is False. So, compiler will exit from the For Loop

Java Program for Natural Numbers in Reverse Example 2

This program is same as first example but this time we are using the While Loop.

// Java Program to Print Natural Numbers in Reverse 
import java.util.Scanner;

public class ReverseNaturalNum2 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int number, i;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the Maximum integer Value : ");
		number = sc.nextInt();	
		
		i = number;
		
		while(i >= 1)
		{
			System.out.print(i +" "); 
			i--;
		}	
	}
}

OUTPUT

Java Program to Print Natural Numbers in Reverse using Method

This program is same as first example but we separated the logic and placed it in the separate method.

// Java Program to Print Natural Numbers in Reverse 
import java.util.Scanner;

public class ReverseNaturalNum3 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int number;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the Maximum integer Value : ");
		number = sc.nextInt();	
		
		ReverseNaturalNumbers(number);	
	}
	
	public static void ReverseNaturalNumbers(int num)
	{
		int i;
		
		for(i = num; i >= 1; i--)
		{
			System.out.print(i +" "); 
		}	
	}
}

OUTPUT

Java Program for Natural Numbers in Reverse between a Range

This program allows the user to enter Minimum and maximum value. Next, the program will print natural numbers between Maximum value  and Minimum value.

// Java Program to Print Natural Numbers in Reverse 
import java.util.Scanner;

public class ReverseNaturalNum4 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int minimum, maximum;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the Minimum value : ");
		minimum = sc.nextInt();			
		
		System.out.print(" Please Enter the Maximum value : ");
		maximum = sc.nextInt();	
		
		ReverseNaturalNumbers(minimum, maximum);
	}
	public static void ReverseNaturalNumbers(int min, int max)
	{
		int i;
		
		for(i = max; i >= min; i--)
		{
			System.out.print(i +" "); 
		}	
	}
}

OUTPUT