如何将此数组按升序排序？

Question

I would like to generate an array of 100 numbers and find their average and sum. I am able to do this but I am not able to get the output of numbers into ascending order. I am super new to Java.

import java.util.Random;

public class randomNumberGen
{
    public static void main(String [] args)
    {
        Random r=new Random();
        double sum = 0; // is double so to prevent int division later on
        int amount = 100;
        int upperBound = 100;

        for (int i = 0; i < amount; i++){
             int next = r.nextInt(upperBound) + 1; // creates a random int in [1,100]
            System.out.println(next);

            sum += next; // accumulate sum of all random numbers
        }

        System.out.println("Your average is: " + (sum / amount));
        System.out.println("Your sum is: " + (sum));        
    }
}

Answer 1

it is very easy. however I didn't see any array in your code. I create an example code for you. you can ask for more help.

public static void main(String[] args) {
    SecureRandom random = new SecureRandom(); // it is better to use this library
    double sum = 0; // is double so to prevent int division later on
    int amount = 100;
    int upperBound = 100;
    int[] array = new int[amount]; // create an array with amount size
    for (int i = 0; i < amount; i++) {
        array[i] = random.nextInt(upperBound) + 1; // creates a random int in [1 , upperBound]
        sum += array[i]; // accumulate sum of all random numbers
    }
    Arrays.sort(array); // sort array in default order which is ascending
    System.out.println(Arrays.toString(array)); // toString is a way to print all of array, without iterate it and print it
    System.out.println("Your average is: " + (sum / amount));
    System.out.println("Your sum is: " + sum);
}

Answer 2

There are a lot of different sorting methods. For a beginner start with either Bubble Sort or Insertion Sort . Insertion Sort is slightly better as on average it runs slightly faster.

Answer 3

I offer to use one of special collections to sort numbers internally, without using one of sorting algorithms (eg us PriorityQueue ):

public static void main(String[] args) {
    final int amount = 100;

    Random random = new SecureRandom();
    Queue<Integer> queue = new PriorityQueue<>(amount, Comparator.naturalOrder());  // Comparator.reverseOrder() for reverse order
    int sum = 0;

    for (int i = 0; i < amount; i++) {
        int val = random.nextInt(100) + 1;
        sum += val;
        queue.add(val);
    }

    System.out.println(Arrays.toString(queue.toArray()));
    System.out.println("Your average is: " + (double)sum / amount);
    System.out.println("Your sum is: " + sum);
}