Question

write a program to find the summ of following series S=1-2+3-4+5-6+.....+19-20​

Answer 1

Answer:

public class Main

{

public static void main(String[] args) {

 int sum=1;

 boolean isMinus=true;

 for (int i=2;i<=20 ;i++ )

 {

     if(isMinus)

     {

          sum=sum-i;

          isMinus=false;

         

     }

     else

     {

          sum=sum+i;

          isMinus=true;

     }

 }

 System.out.println(sum);

}

}

Explanation:

Here's the Java program