Sum of First N Natural Numbers in Java Example

In this example, the sum of first 10 natural numbers is displayed. First, input the value of n (10 in this case) i.e. number of natural numbers whose sum is to be calculated. Then, after initializing the variables i to 1 and sum to 0, we enter the do-while loop. The execution of the body of loop continues as long as condition (i<=n) evaluates to true. When variable 1’s is value becomes 11, the condition becomes false and this terminates the do-while loop and program execution continues with the next statement after the loop which displays the sum of first 10 natural numbers.

//Program to Find Sum of First N Natural Numbers 
  import java.util.Scanner; //Program uses Scanner class 
 public class SumNatural 
  { 
      public static void main(String[] args) 
      { 
         int n,i=1,sum=0; 
         Scanner input=new Scanner(System.in); 
         System.out.print("Enter Number :"); 
         n=input.nextInt(); 
         do 
             { 
                  sum=sum+i; 
                  i +=1; 
             }   while(i<=n); 
                  System.out.print("Sum of First " + n + " Numbers = "+sum); 
      } 
       
 }