Identify and correct errors in the following program: public class Chapter7Ex9 { public static void main(String[] args) { System.out.println(signum(12)); System.out.println(signum(-11)); System.out.println(signum(20.5)); System.out.println(signum(0)); } public static int signum(int x) { if (x > 0) return 1; else if (x == 0) return 0; else return -1; }