Java基础语法23-数组练习

Java基础语法23-数组练习

1.计算二维数组数值的总和

public class ArrayExer {
    public static void main(String[] args) {
        int[][] arr = new int[][]{{3,5,8},{12,9},{7,0,6,4}};
        int sum = 0;
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                sum+=arr[i][j];
            }
        }
        System.out.println("总和为："+sum);
    }
}

2.使用二维数组打印一个杨辉三角

public class ArrayExer {
    public static void main(String[] args) {
        //1.声明并初始化二维数组
        int[][] yanghui = new int[10][];

        //2.给数组的元素赋值
        for (int i = 0; i < yanghui.length; i++) {
            yanghui[i] = new int[i + 1];
            //2.1给首末元素赋值
            yanghui[i][0] = yanghui[i][i] = 1;
            //2.2给每行的非首末元素赋值
            if (i > 1) {
                for (int j = 1; j < yanghui[i].length - 1; j++) {
                    yanghui[i][j] = yanghui[i - 1][j] + yanghui[i - 1][j - 1];

                }
            }
        }

        //3.遍历二维数组
        for (int i = 0; i < yanghui.length; i++) {
            for (int j = 0; j < yanghui[i].length; j++) {
                System.out.print(yanghui[i][j]+"    ");

            }
            System.out.println();
        }

    }
}