exception in thread main java.lang.arrayindexoutofboundsexception 1 - arrays

Question

well i have to make a java program which determinate if a given number is capicua(131,12121,13431) the same number from last to initial digit. but it gives me the error, in the line 23 (while(i>=0).....) the question is how can i call the array into thath while. pls help me im really sad :c. Here is the code:
public class Capi {
/**
*
**/
public static int num(int a) { // counting digits from the number
int n = 0;
while(a>=10) { a = a/10;
n = n+1;
}
return n;
}
public static boolean det(int a, int n) {
int z = a;
double y =0;
n = n-1;
int i = 0;
int x[] = new int[n];
for(i=0; i<x.length; i++) { // saving the digits into x[i]
x[i] = a%10;
a = a/10;
}
while(i>=0) { y = x[i]*Math.pow(10,n-1); // calling the digits x[i],x[i-1] untill it gets 0
i = i - 1;
n = n -1;
}
double num1= y + a*Math.pow(10,n);
if(num1 == z) { return true; }
else { return false; }
}
}

Answer 1

I feel the issue is that the value of i is set to x.length, before you attempt while(i>=0). I have hence added i-- before you run the loop.
See if the following does the trick.
public class Capi {
public static int num(int a) { // counting digits from the number
int n = 0;
while(a>=10) {
a = a/10;
n = n+1;
}
return n;
}
public static boolean det(int a, int n) {
int z = a;
double y = 0;
n = n-1;
int i = 0;
int x[] = new int[n];
for(i=0; i<x.length; i++) { // saving the digits into x[i]
x[i] = a%10;
a = a/10;
}
//i is now set to x.length, thus decrement it as index runs from 0 to x.length-1
i=i-1;
while(i>=0) {
y = x[i]*Math.pow(10,n-1); // calling the digits x[i],x[i-1] untill it gets 0
i = i - 1;
n = n -1;
}
double num1= y + a*Math.pow(10,n);
if(num1 == z) {
return true;
}
else {
return false;
}
}
}