Write a program to find an number in array of integers using Binary Search using c#

Hi
Refer below program.

    int[] arr = { 23, 56, 67, 78, 89, 90, 94, 95, 96, 97, 99 };
    int key = 97;
    int minNum = 0;
    int maxNum = arr.Length - 1;
    while (minNum <= maxNum)
    {
        int mid = (minNum + maxNum) / 2;
        if (key == arr[mid])
        {
            ++mid;
            break;
        }
        else if (key<arr[mid])
        {
            maxNum = mid - 1;
        }
        else
        {
            minNum = mid + 1;
        }
    }