java输出一个杨辉三角

以下是Java代码，可以输出一个杨辉三角：

import java.util.Scanner;

public class YangHuiTriangle {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入杨辉三角的行数：");
        int n = scanner.nextInt();
        int[][] arr = new int[n][n];
        for (int i = 0; i < n; i++) {
            arr[i][0] = 1;
            arr[i][i] = 1;
        }
        for (int i = 2; i < n; i++) {
            for (int j = 1; j < i; j++) {
                arr[i][j] = arr[i - 1][j - 1] + arr[i - 1][j];
            }
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j <= i; j++) {
                System.out.print(arr[i][j] + " ");
            }
            System.out.println();
        }
    }
}