题解 | #箭形图案#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       while(sc.hasNextInt()){
        int num = sc.nextInt();
        for (int i = 1;i<=num+1;i++){
            for (int j =i;j<=num;j++ ){
                System.out.print("  ");
            }
            for(int k = 1;k<=i;k++){
                System.out.print("*");
            }
            System.out.println();
        }
        for (int i = 1;i<=num;i++){
            for (int j = 1;j<=i;j++){
                System.out.print("  ");
            }
            for (int j = num;j>=i;j--){
                System.out.print("*");
            }
            System.out.println();
        }
       }
    }
}