using System;

public class Program

{

    private static void ClearExceptCircle(int[,] array, int row, int column, int radius) {

      int rowCount = array.GetLength(0);

      int colCount = array.GetLength(1);

​

      for (int r = 0; r < rowCount; ++r)

        for (int c = 0; c < colCount; ++c)

          if ((row - r) * (row - r) + (column - c) * (column - c) > radius * radius)

            array[r, c] = 0;

    }

    private static void Show(int[,] array) {

       int rowCount = array.GetLength(0);

       int colCount = array.GetLength(1);    

       for (int r = 0; r < rowCount; ++r) {

         if (r > 0)  

           Console.WriteLine();    

         for (int c = 0; c < colCount; ++c) {

           if (c > 0)   

             Console.Write(' ');   

           Console.Write(array[r, c]);   

         }

       }

    }        

    private static int[,] Build(int rows, int cols) {

      int[,] result = new int[rows, cols];

      for (int r = 0; r < rows; ++r)    

        for (int c = 0; c < cols; ++c)    

          result[r, c] = (c + 1) % 10;  

      return result;    

    }

    public static void Main()

    {

      Console.WriteLine("Before:");

      Console.WriteLine("");         

      int[,] array = Build(5, 10);

      Show(array);  

      Console.WriteLine("");    

      Console.WriteLine("");

      Console.WriteLine("After:");

      Console.WriteLine("");    

      ClearExceptCircle(array, 2, 4, 2);    

      Show(array);      

    }

}