Unique Number problem

#1

Why I am getting 0 while passing in every inputs

#include
using namespace std;
int main() {
int n,ans=0;
cin>>n;
int a[n];
for(int i=0;i<n;i++)
{
//int no;
cin>>a[i];
int ans = ans^a[i];
}
cout<<ans;
return 0;
}

#2

Why you are redifining
ans
In the for loop as “int ans=ans^a[i]”
Fix this