🧮 Java Program to Print First N Natural Numbers

📝 Introduction

Natural numbers are the numbers used for counting — starting from 1, 2, 3, 4, 5, ... and so on.
In this Java program, we’ll learn how to print the first N natural numbers, where N is provided by the user.

This is one of the simplest programs to start learning loops and input handling in Java.

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⚙️ Logic Behind the Program

1. Accept the number N from the user.

2. Use a for loop to print numbers from 1 to N.

3. Each number is printed in the same line (or separately depending on your choice).

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💻 Java Code

// Java program to print first N natural numbers
import java.util.Scanner;

public class NaturalNumbers {
    public static void main(String[] args) {
        
        // Create Scanner object to take input from user
        Scanner sc = new Scanner(System.in);

        // Asking the user to enter a number
        System.out.print("Enter the value of N: ");
        int n = sc.nextInt();

        // Display message
        System.out.println("The first " + n + " natural numbers are:");

        // Loop from 1 to n
        for (int i = 1; i <= n; i++) {
            System.out.print(i + " ");
        }

        // Close scanner
        sc.close();
    }
}

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🧠 Explanation of the Code

Line	Explanation
import java.util.Scanner;	Imports the Scanner class for user input.
Scanner sc = new Scanner(System.in);	Creates a Scanner object to read input.
int n = sc.nextInt();	Takes the number (N) from the user.
for (int i = 1; i <= n; i++)	Loop starts from 1 and runs until it reaches N.
System.out.print(i + " ");	Prints numbers in the same line separated by spaces.

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🧾 Example Output

Input:

Enter the value of N: 5

Output:

The first 5 natural numbers are:
1 2 3 4 5

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💡 Alternative: Using While Loop

You can also use a while loop to achieve the same result:

import java.util.Scanner;

public class NaturalNumbersWhile {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the value of N: ");
        int n = sc.nextInt();

        int i = 1;
        while (i <= n) {
            System.out.print(i + " ");
            i++;
        }
        sc.close();
    }
}

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🏁 Conclusion

This program is a great starting point to understand:

• Loops (for and while)

• User input using Scanner

• Basic logic building in Java