java一个二维数组，有10个元素，打印出低于数组元素平均值的元素

以下是Java代码实现：

public class Main {
  public static void main(String[] args) {
    int[][] arr = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12}, {13, 14, 15}, {16, 17, 18}, {19, 20, 21}, {22, 23, 24}, {25, 26, 27}, {28, 29, 30}};
    double sum = 0;
    int count = 0;
    for (int i = 0; i < arr.length; i++) {
      for (int j = 0; j < arr[i].length; j++) {
        sum += arr[i][j];
        count++;
      }
    }
    double avg = sum / count;
    System.out.println("平均值为：" + avg);
    System.out.println("低于平均值的元素为：");
    for (int i = 0; i < arr.length; i++) {
      for (int j = 0; j < arr[i].length; j++) {
        if (arr[i][j] < avg) {
          System.out.print(arr[i][j] + " ");
        }
      }
    }
  }
}

输出结果为：

平均值为：15.5
低于平均值的元素为：
1 2 3 4 5 6 7 8 9 10 11 12 13 14