C#Exams 3. Disk (on Java Code)

import java.util.Scanner;

public class _3_Disk {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scan = new Scanner(System.in);
        int size = scan.nextInt();
        int radius = scan.nextInt();

        int outerDotsMinWidth = (size / 2) - radius;
        int squareRadius = radius * radius;
        String outerDotSeq;
        String asteriskSeq;
        int x, y;
        for (int row = 0; row < size; row++) {
            if (row < outerDotsMinWidth || row > (size - 1) - outerDotsMinWidth) {
                System.out.println(newString('.', size));
            } else if (row == (size / 2)) {
                asteriskSeq = newString('*', (2 * radius) + 1);
                outerDotSeq = newString('.', outerDotsMinWidth);
                System.out.printf("%1$s%2$s%1$s\n", outerDotSeq, asteriskSeq);
            } else if (row == outerDotsMinWidth
                    || row == (size - 1) - outerDotsMinWidth) {
                System.out.printf("%1$s*%1$s\n", newString('.', size / 2));
            } else if ((row > outerDotsMinWidth && row < (size / 2))
                    || (row > (size / 2) && row < (size - 1)
                            - outerDotsMinWidth)) {
                y = (size / 2) - row;
                x = (int) Math.sqrt(squareRadius - (y * y));
                asteriskSeq = newString('*', (2 * x) + 1);
                outerDotSeq = newString('.', (size - (2 * x) - 1) / 2);
                System.out.printf("%1$s%2$s%1$s\n", outerDotSeq, asteriskSeq);
            }
        }
    }

    private static String newString(char ch, int size) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < size; i++) {
            sb.append(ch);
        }

        return sb.toString();
    }
}