取数组中元素的平均值

Question

So I'm getting ready for a quiz tomorrow and I was playing around with arrays, I'm asking for how many tests the user wants to input then ask for every score of a test. the trouble im having is summing up the tests, it doesn't sum all up, please help me

import java.util.Scanner;

public class Arrays {
    public static void main(String args []){
        int numOfElements;

        Scanner input = new Scanner(System.in) ;

        System.out.println("How many tests are you going to input? ");
        numOfElements = input.nextInt();

        double array[] = new double [numOfElements];

        for (int i=0; i<array.length; i++){
            System.out.println("Enter the test # " + (i+1) + ": ");
            array[i] = input.nextDouble();
        }


        for (int i = 0; i<array.length; i++ )
        {

            System.out.print("Test #"+(i+1)+"= "+array[i] + " pts\n");

        }


        for (int m= 0; m<array.length; m++)
        {   //average value

            double sum = 0;

            sum = sum + array[m]; //get the sum\

            double average = sum / array.length; //get the average value


            //print out the sum of elements in an array

            System.out.print("Your total points are: "+sum);

            //print out the average grade

            System.out.println("Your grades is "+average +"%");
        }


    }

Answer 1

Your problem is here:

double sum = 0

That resets your counter during each loop iteration!

So, for starters, you have to move that statement in front of your for loop! Same for 'average'!

Answer 2

You should sum up the scores in the loop. After that , you print the results.

double sum = 0;
for (int m= 0; m<array.length; m++)
{   //average value

    sum = sum + array[m]; //get the sum\


}

double average = sum / array.length; //get the average value


//print out the sum of elements in an array

System.out.print("Your total points are: "+sum);

//print out the average grade

System.out.println("Your grades is "+average +"%");

Answer 3

double sum and double average are reset every iteration, declare them as local variables outside the for-loop, and print average and sum once the iteration is completed

    double sum = 0;
    for (int m = 0; m < array.length; m++) {
        sum = sum + array[m];
    }
    System.out.print("Your total points are: " + sum);
    System.out.println("Your grades is " + sum / array.length + "%");

In java8+

    double array[] = new double[numOfElements];
    DoubleSummaryStatistics dss = Arrays.stream(array).summaryStatistics();
    System.out.println("average " + dss.getAverage());
    System.out.println("sum " + dss.getSum());