Java Program to Calculate the Sum of Natural Numbers

In this article, we will understand how to calculate the sum of natural numbers in Java. All possible positive numbers from 1 to infinity are called natural numbers.

Below is a demonstration of the same −

Input

Suppose our input is −

50 and 100

Output

The desired output would be −

Sum of natural numbers from 50 to 100 is 3825

Algorithm

Step1- Start
Step 2- Declare three integers my_lower_limit , my_upper_limit, sum.
Step 3- Prompt the user to enter two integer value/ define the integers
Step 4- Read the values
Step 5- Run a for-loop, add the number with its next number until the upper limit is reached.
Store the sum in a variable.
Step 6- Display the result
Step 7- Stop

Example 1

Here, the input is being entered by the user based on a prompt. You can try this example live in ourcoding ground tool .

import java.util.Scanner;
public class NaturalNumbersSum {
   public static void main(String[] args) {
      int my_lower_limit , my_upper_limit, sum;
      System.out.println("Required packages have been imported");
      Scanner scanner = new Scanner(System.in);
      System.out.println("A scanner object has been defined ");
      System.out.print("Enter the starting number: ");
      my_lower_limit = scanner.nextInt();
      System.out.print("Enter the max number: ");
      my_upper_limit = scanner.nextInt();
      sum = 0;
      for(int i = my_lower_limit; i <= my_upper_limit; ++i){
         sum += i;
      }
      System.out.println("The sum of natural numbers from " + my_lower_limit + " to " + my_upper_limit + " is " +sum);
   }
}

Output

Required packages have been imported
A scanner object has been defined
Enter the starting number: 50
Enter the max number: 100
The sum of natural numbers from 50 to 100 is 3825

Example 2

Here, the integer has been previously defined, and its value is accessed and displayed on the console.

public class NaturalNumbersSum {
   public static void main(String[] args) {
      int my_input_1 , my_input_2, sum;
      my_input_1 = 50;
      my_input_2 = 100;
      sum = 0;
      System.out.println("The first and last numbers are defined as " +my_input_1 +" and "+my_input_2 );
      for(int i = my_input_1; i <= my_input_2; ++i){
         sum += i;
      }
      System.out.println("The sum of natural numbers from " + my_input_1 + " to " + my_input_2 + " is " +sum);
   }
}

Output

The first and last numbers are defined as 50 and 100
The sum of natural numbers from 50 to 100 is 3825