first repeating character in a string
// C# program to find the first
// repeated character in a string
using System;
using System.Collections.Generic;
class GFG
{
// This function prints the first
// repeated character in str[]
public static char firstRepeating(char[] str)
{
// Creates an empty hashset
HashSet<char> h = new HashSet<char>();
// Traverse the input array
// from left to right
for (int i = 0; i <= str.Length - 1; i++)
{
char c = str[i];
// If element is already in hash set,
// update x and then break
if (h.Contains(c))
{
return c;
}
else // Else add element to hash set
{
h.Add(c);
}
}
return '\0';
}
// Driver Code
public static void Main(string[] args)
{
string str = "geeksforgeeks";
char[] arr = str.ToCharArray();
Console.WriteLine(firstRepeating(arr));
}
}