Java Programs Made Easy

Q)... Retrieve the odd numbers till given input number. add and subtract it consecutively and return the result.
Input:9
Output:1+3-5+7-9=-3

1. package Set1;
2. import java.util.*;
3. public class ClassSet7 {
4.  public static int consecutiveSumSubofOddNos(int n){
5.   List<Integer> l1=new ArrayList<Integer>();
6.   for(int i=1;i<=n;i++)
7.    if(i%2!=0)
8.     l1.add(i);
9.   int n1=l1.get(0);
10.   for(int i=1;i<l1.size();i++)
11.    if(i%2!=0)
12.     n1=n1+l1.get(i);
13.    else
14.     n1=n1-l1.get(i);
15.   return n1;
16.  }
17.  public static void main(String[] args) {
18.   Scanner s=new Scanner(System.in);
19.   int n=s.nextInt();
20.   System.out.println(consecutiveSumSubofOddNos(n));
21.  }
22. }