JAVA，数组的平均值的做法

 public static void main(String[] args){
        int[]  num={89,78,85,67,92,74,99,81};
        double avg;
        double sum=0;
        System.out.println("输出：");
        for (int n=0;n<num.length;n++){
            System.out.print(num[n]+"\t");
            sum=sum+num[n];
        }
        avg=sum/8;
        System.out.println("");
        System.out.println(avg);
    }

public class Test {
    public static void main(String[] args) {
        int[] a = {89,78,85,67,92,74,99,81};
        int sum = 0;
        double avg;
        for(int i=0;i<a.length;i++){
            sum += a[i];
            System.out.print(a[i]+" ");
        }
        avg = sum*1.0/a.length;
        System.out.println();
        System.out.println(avg);
    }
}

import java.util.*;

public class A {
    public static void main(String[] args) {
        int[] arr = new int[10];
        double sum = 0;
        Scanner sc = new Scanner(System.in);
        for(int i = 0;i < 8;i++){
            arr[i] = sc.nextInt();
            sum += arr[i];
        }
        System.out.println(sum / 8);
    }
}

求和：
System.out.println(Arrays.stream(arr).reduce(Integer::sum).getAsInt());
求平均：
System.out.println(Arrays.stream(arr).average().getAsDouble());