绘制星号菱形

Question

我有一个程序，您可以在其中输入一个数字，然后它会将其打印成钻石。我已经对齐并弄清楚了上半部分，只是无法对齐下半部分。它应该增加星号的数量，然后又减少到一个。

import java.util.Scanner;
public class Diamonds
{
    public static void main(String args[])
    {
        int n, i, j, space = 0;
        System.out.print("Enter the number of rows: ");
        Scanner s = new Scanner(System.in);
        n = s.nextInt();
        space = n - 0;
        for (j = 0; j <= n; j++)
        {
            for (i = 0; i < space; i++)
            {
                System.out.print(" ");
            }
                System.out.print("   ");
            space--;
            for (i = j; i <= 2 * j - 1; i++)
            {
                System.out.print("* ");
            }
            System.out.println("   ");
        }
        space = 0;
        for (j = n - 1  ; j > 0; j--)
        {
            for (i = 0; i <= i - n; i++)
            {
                System.out.print("   ");
            }

            System.out.print(" ");

            space--;

            for (i = j; i <= 2 * j - 1; i++)
            {
                System.out.print(" *");
            }
            System.out.println("  c ");
            space=n-1;
        }
    }
}

Answer 1

我将您的输入移至选项窗格中并清理了一些其他代码：

public static void main(String [] args) {
    try {
        String amt = JOptionPane.showInputDialog("Enter number of rows:");
        int n = Integer.valueOf(amt);
        int space = n;
        for (int j = 0; j <= n; j++) {
            StringBuilder builder = new StringBuilder();
            IntStream.range(0, space).forEach(i -> builder.append(' '));
            builder.append("   ");
            space--;
            IntStream.range(j, 2*j).forEach(i -> builder.append("* "));
            System.out.println(builder);
        }
        space++;
        for (int j = n - 1; j > 0; j--) {
            space++;
            StringBuilder builder = new StringBuilder();
            IntStream.range(0, space).forEach(i -> builder.append(' '));
            builder.append("   ");
            IntStream.range(j, 2*j).forEach(i -> builder.append("* "));
            System.out.println(builder);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}