Expection

Question

Expection in thread"main"java.lang.ArrayIndexOutOfBoundsExpection:0 at ReverseOrder.main<ReverseOrder.java:19>
How can I fix it??
import java.util.*;
public class ReverseOrder {
     static int counter = 0;
     public static void main(String[] args) {
          reverse("", args[0]);
     public static void reverse(String a, String b)  {
     //recursively
     if(b.length()==1)
     System.out.println(b);
     else
     System.out.println(b.charAt(b.length()-1));
     reverse(a, b.substring(0,b.length()-1));
}

Answer 1

Hi there,
Problem here is that the recursive call doesn't have a termination condition. As such it will keep calling itself which causes the charAt() to point to negative index thereby throwing an Exception.
Simple workaround is to include the recursive call within else:
if(b.length()==1) {
     System.out.println(b);
} else {
     System.out.println(b.charAt(b.length()-1));
     reverse(a, b.substring(0,b.length()-1));
this way, the function will stop calling itself when charAt reaches the first character of string b.
Expection in
thread"main"java.lang.ArrayIndexOutOfBoundsExpection:0
at ReverseOrder.main<ReverseOrder.java:19>
How can I fix it??
import java.util.*;
public class ReverseOrder {
     static int counter = 0;
     public static void main(String[] args) {
          reverse("", args[0]);
     public static void reverse(String a, String b)  {
     //recursively
     if(b.length()==1)
     System.out.println(b);
     else
     System.out.println(b.charAt(b.length()-1));
     reverse(a, b.substring(0,b.length()-1));