9.20java学习

 1 package staticDemo1;
 2 
 3 public class Test1 {
 4     public static void main(String[] args) {
 5         int[] arr1={1,2,3,4,5};
 6         System.out.println(Arrunit.printArr(arr1));
 7         double[] arr2={1.1,2.2,3.3,4.4};
 8         System.out.println(Arrunit.acv(arr2));
 9     }
10 }

 1 package staticDemo1;
 2 
 3 public class Arrunit {
 4     private Arrunit(){
 5     }
 6     public static String printArr(int[] arr){
 7         StringBuilder sb = new StringBuilder();
 8         sb.append("[");
 9         for (int i = 0; i < arr.length; i++) {
10             if(i==arr.length-1){
11                 sb.append(arr[i]);
12             }else {
13                 sb.append(arr[i]);
14                 sb.append(",");
15             }
16         }
17         sb.append("]");
18         return sb.toString();
19     }
20     public static double acv(double[] arr){
21         double sum=0;
22         for (int i = 0; i < arr.length; i++) {
23             sum=sum + arr[i];
24         }
25         return sum/arr.length;
26     }
27 }