How to make the output print the first position of every three identical numbers? (in this case 4 {position number 3} and 7 {position number 8)?

int counter = new int();
int[] arr = {1,2,3,4,4,4,5,6,7,7,7};
         
for (int i = 0; i < arr.Length; i++)
{
  if (arr[i] == arr[i+1]) // it says "Index was outside the bounds of the array."
  {
    counter++;
    if (counter == 2)
    {
      Console.WriteLine(arr[i] + " "); 
    }
  }
}
Console.ReadKey();

>Solution :

You must iterate through you array and check for equality 3 numbers in a row

int[] arr = { 1, 2, 3, 4, 4, 4, 5, 6, 7, 7, 7 };

for (int i = 0; i < arr.Length - 2; i++)
{
    if (arr[i] == arr[i + 1] && arr[i] == arr[i + 2])
    {
        Console.WriteLine("Trio is at:" + i + " Value is" + arr[i]);
    }
}

Console.ReadKey();