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Java Program to print Sum of N Even numbers

Get input n and print n even numbers.

Sample Input 1:

7

Sample Output 1:

The sum of N Even numbers:56

Program or Solution

				
			
					
import java.util.*;
class SumOfNEven
 {
    public static void main(String args[])
    {
       int i,j,N,sum=0;
       System.out.println("Enter The Value Of N");
       Scanner sc=new Scanner(System.in);
       N=sc.nextInt();

       for(j=1,i=2;j<=N;i=i+2,j++)
       {
            sum=sum+i;
       }
            System.out.println("The Sum Of N Even Numbers: "+sum);
    }
}

Program Explanation

1.    Get input N (How many even numbers to be summed)

2.     Instruction(s) inside the for block{} are executed repeatedly till the second expression (j<=N) is true.

        for(j=1,i=2;j<=N;i=i+2,j++)

3.    Here i is initialized to 2 and j is initialized to 1 and i is incremented by 2 and  j is incremented by 1 for each           iteration.

       instructions inside the for block are executed in every iteration and iteration stops when j becomes                       greater than N. so value of i (2,4,6... ) will be added to sum.

        so even numbers (i) are added to the sum for j --> 1 to N times

        sum = sum + j

        sum = 0 + 2

        sum = 2 + 4

        sum = 6 + 6

        sum = 12 + 8

        ..................

        ..................

        after adding all N even numbers to sum, sum will be printed using system.out.println().

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