Loops.java

public class Loops{

    public static void main(String[] args){

        Scanner in = new Scanner(System.in);

        int rows = 0;

        System.out.print("Chose a number: ");

        while (in.hasNextInt()) {
            rows = in.nextInt();

            if (rows >= 2 && rows <= 20) {
                break;
            }

            System.out.println("Please choose a number between 2 and 20");
        }

        for (int i = rows; i > 0; i--) {
            for (int k = rows - i; k > 0; k--) {
                System.out.print(" ");
            }

            for (int j = 0; j < i; j++) {
                System.out.print("*");
            }

            System.out.print(" ");

            for (int k = 0; k < rows + 1 - i; k++) {
                System.out.print("*");
            }

            for (int l = 0; l < i; l++) {
                System.out.print(" ");
            }

            for (int m = i; m > 1; m--) {
                System.out.print(" ");
            }

            for (int n = rows + 1 - i; n > 0; n--) {
                System.out.print("*");
            }

            System.out.print(" ");

            for (int p = i; p > 0; p--) {
                System.out.print("*");
            }
	}
    }
}