Java实现杨辉三角

import java.util.Scanner;

/**
 * Created by intellij IDEA
 * Author:Raven
 * Date:2018/2/25
 * Time:12:32
 */
public class YFTriangle {
    public static void main(String[] args) {
        printTriangle();
    }

    /**
     * 杨辉三角在新位置的特定元素=原来该位置的元素+前一个位置的元素
     * */
    private static void printTriangle() {
        System.out.println("输出多少行：");
        Scanner scanner = new Scanner(System.in);
        int lines = scanner.nextInt();
        if (lines <= 0){
            try {
                throw new Exception("请输入大于0的行数");
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        int[] a = new int[lines + 1];
        int previous = 1;

        for (int i = 1; i <= lines; i++) {
            for (int j = 1; j <= i; j++) {
                int current = a[j];
                a[j] = previous + current;
                previous = current;
                System.out.print(a[j] + " ");
            }
            System.out.println();
        }

    }
}