#include <bits/stdc++.h>
using namespace std;
// Returns first repeating character in str.
char firstRepeating(string &str)
{
// Creates an empty hashset
unordered_set<char> h;
// Traverse the input array from left to right
for (int i=0; i<str.length(); i++)
{
char c = str[i];
// If element is already in hash set, update x
// and then break
if (h.find(c) != h.end())
return c;
else // Else add element to hash set
h.insert(c);
}
// If there was no repeated character
return '\0';
}
// Driver method to test above method
int main ()
{
string str = "Helooq";
cout << firstRepeating(str);
return 0;
}
