Java Program to Print All Natural Numbers from 1 to N in Iterative Methods

Java program to print all the natural numbers from 1 to N can be written in both iterative and recursive methods. In the iterative method, the task can be performed by using for loop, while loop and do-while loop. Here, all the Java programs using different loops have been covered to print the natural numbers from 1 to N (1, 2, 3, ..., N).

Page content(s):

1. Program & Output

Additional content(s):

1. Algorithm

2. Pseudocode

3. Time Complexity

4. Flowchart

1. Java Program & output to Print First N Natural Numbers

Code has been copied

/**************************************************
                alphabetacoder.com
 Java program to print all natual numbers  
 from 1 to n using for loop
**************************************************/

import java.util.Scanner;
public class PrintNumbers {
    public static void main(String args[]) {
        //System.in is a standard input stream
        // sc is the object
        Scanner sc = new Scanner(System.in);
        int n, i;

        //take input of the number upto 
        // which numbers will be printed
        System.out.print("Enter the upper limit=");
        n = sc.nextInt();

        // iterate from 1 to n and print the number
        System.out.print("First " + n + " natural numbers are : ");
        for (i = 1; i <= n; i++) {
            System.out.print(i + " ");
        }
    }
}

Output

Case 1:

Enter the upper limit=10

First 10 natural numbers are : 1 2 3 4 5 6 7 8 9 10

Case 2:

Enter the upper limit=5

First 5 natural numbers are : 1 2 3 4 5

/**************************************************
                alphabetacoder.com
 Java program to print all natual numbers  
 from 1 to n using while loop
**************************************************/

import java.util.Scanner;
public class PrintNumbers {
    public static void main(String args[]) {
        //System.in is a standard input stream
        // sc is the object
        Scanner sc = new Scanner(System.in);
        int n, i;

        //take input of the number upto 
        // which numbers will be printed
        System.out.print("Enter the upper limit=");
        n = sc.nextInt();

        // iterate from 1 to n and print the number
        System.out.print("First " + n + " natural numbers are : ");
        i = 1;
        while (i <= n) {
            System.out.print(i + " ");
            i++;
        }
    }
}

Output

Case 1:

Enter the upper limit=10

First 10 natural numbers are : 1 2 3 4 5 6 7 8 9 10

Case 2:

Enter the upper limit=5

First 5 natural numbers are : 1 2 3 4 5

/**************************************************
                alphabetacoder.com
 Java program to print all natual numbers  
 from 1 to n using do-while loop
**************************************************/

import java.util.Scanner;
public class PrintNumbers {
    public static void main(String args[]) {
        //System.in is a standard input stream
        // sc is the object
        Scanner sc = new Scanner(System.in);
        int n, i;

        //take input of the number upto 
        // which numbers will be printed
        System.out.print("Enter the upper limit=");
        n = sc.nextInt();

        // iterate from 1 to n and print the number
        System.out.print("First " + n + " natural numbers are : ");
        i = 1;
        do {
            System.out.print(i + " ");
            i++;
        } while (i <= n);
    }
}

Output

Case 1:

Enter the upper limit=10

First 10 natural numbers are : 1 2 3 4 5 6 7 8 9 10

Case 2:

Enter the upper limit=5

First 5 natural numbers are : 1 2 3 4 5