Question

write a program to find the sum of first n even natural numbers​

Answer 1

Answer:

Explanation:

Given a number n. The problem is to find the sum of first n even numbers.

Examples:  

 Input : n = 4

Output : 20

Sum of first 4 even numbers

= (2 + 4 + 6 + 8) = 20  

Input : n = 20

Output : 420

Answer 2

Answer:

import java.util.Scanner;

class sumofnaturalevennum

{

    public static void main(String args[])

    {

          Scanner input = new Scanner(System.in);

          System.out.println("Enter n : ");

          int n = input.nextInt();

          int sum = 0;

          int num = 1;

          for(int count=1; count<=n; ){  

     if(num%2 == 0){

         sum += num;

         count++;

     }

     num++;

 }

System.out.println("Sum: "+sum);

}

}

Explanation: