Question

I am doing a maths challenge for project euler and i have come across a strange problem when running the program. The result should be the sum of all the odd numbers up to 10,000,000 but i get a negative number, what am i doing wrong?

package program;

import java.util.*;

public class MainClass {

/**
 * @param args
 */
public static void main(String[] args) {

    int total = 0;

    for (int counter = 1; counter < 10000000; counter++) {
        if (!((counter % 2) == 0)) {
            total+=counter;
        }

    }
    System.out.println(total);

}

}

Answer 1

Use a long instead of an int. You’re getting a negative number due to integer overflow.