public class Main {

    public static void main(String[] args) {

        System.out.println(sumOdd(0, 100)); 

        // output is 2500

    }

    public static boolean isOdd (int number) {

        if (number <= 0) {

            return false;

        } else if (number == 1) {

            return true;

        }

        for (int i = 1; i <= number / 2; i++) {

            i += i;

            if ((number % i) == 1) {

                return true;

            }

        }

        return false;

    }

    public static int sumOdd (int start, int end) {

        if ((start < 0 || end < 0) || (start > end)) {

            return -1;

        }

        int sum = 0;

        for  (int i = start; i <= end; i++) {

            if (isOdd(i)) {

                sum = sum + i;

            }

        }

        return sum;

    }

}

import java.util.*;

​

public class Main {

    void Sum(int num) {

        int arr[] = new int[num];

        System.out.println("Enter the numbers");

        Scanner sc = new Scanner(System.in);

        for (int i = 0; i < num; i++) {

            arr[i] = sc.nextInt();

        }

        System.out.print("The numbers are : ");

        for (int i = 0; i < num; i++) {

            System.out.print(arr[i] + " ");

        }

        int oddSum = 0;

        int evenSum = 0;

        for (int i = 0; i < num; i++) {

            if (arr[i] % 2 == 0) {

                evenSum += arr[i];

            } else {

                oddSum += arr[i];

            }

        }

        System.out.println("\nSum of even numbers: " + evenSum);

        System.out.println("Sum of odd numbers: " + oddSum);

    }

    public static void main(String[] args) {

        Scanner s = new Scanner(System.in);

        System.out.println("Enter the number of elements : ");

        int n = s.nextInt();

        Main obj = new Main();

        obj.Sum(n);

    }

}