import java.math.BigDecimal;/*** 求以下double数组的平均值(四舍五入保留两位小数)：* double[] arr = {0.1,0.2,2.1,3.2,5.56,7.21};*/
public class Demo1 {public static void main(String[] args) {double[] arr = new double[]{0.1, 0.2, 2.1, 3.2, 5.56, 7.21};double count = 0;for (double d : arr) {count += d;}//数组的平均值(四舍五入保留两位小数)：System.out.println("和：" + count + " - 个数: " + arr.length + "平均值: " + count / arr.length);//获得，和的Big对象BigDecimal bgCount = new BigDecimal(String.valueOf(count));//获得数组个数的Big对象BigDecimal bgAverage = new BigDecimal(String.valueOf(arr.length));//调用BigDecimal的除方法，保留两位小数，向上取整BigDecimal average = bgCount.divide(bgAverage, 2, 2);System.out.println(average);}
}