toString、求平均数工具类

 1  /**
 2      * 构造器私有化
 3      */
 4     private ArraysUtils(){}
 5 
 6     //  toString()工具类   静态方法、工具方法
 7     public static String toString(int[] arr){
 8         String result = "[";
 9         for (int i = 0; i < arr.length; i++) {
10             result += (i == arr.length -1 ? arr[i] : arr[i] + ", ");
11         }
12         result += "]";
13         return result;
14     }
15 
16     //  求平均分。静态方法工具方法
17     public static double average(int[] arr){
18         int max = arr[0];
19         int min = arr[0];
20         int mean = 0;
21         for (int i = 0; i < arr.length; i++) {
22             if (arr[i] > max){
23                 max = arr[i];
24             }
25             if (arr[i] < min){
26                 min = arr[i];
27             }
28             mean += arr[i];
29         }
30 
31         return (mean - max - min) / (arr.length - 2) * 1.0;
32     }

1  public static void main(String[] args) {
2         int[] arr = {10, 20, 30};
3         System.out.println(arr);
4         System.out.println(ArraysUtils.toString(arr));
5         System.out.println(ArraysUtils.average(arr));
6 
7     }