The challenge
Given a number, find its opposite.
Examples:
1: -1
14: -14
-34: 34
The solution in Java
We return the number itself multiplied by a negative 1.
public class Solution {
public static int opposite(int number) {
return number *= -1;
}
}
This can be simplified further as:
public class Solution {
public static int opposite(int number) {
return -number;
}
}
There is also a built in method to help with this if you prefer, called Math.negateExact():
public class Solution {
public static int opposite(int number) {
return Math.negateExact(number);
}
}
Test cases to validate our solution
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class OppositeExampleTests {
@Test
public void tests() {
assertEquals(-1, Solution.opposite(1));
assertEquals(0, Solution.opposite(0));
assertEquals(25, Solution.opposite(-25));
}
}
