如何將此數組按升序排序？

Question

我想生成一個包含 100 個數字的數組並找到它們的平均值和總和。 我能夠做到這一點，但我無法將數字的輸出按升序排列。 我是 Java 的新手。

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

這很容易。 但是我在您的代碼中沒有看到任何數組。 我為您創建了一個示例代碼。 你可以尋求更多幫助。

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

有很多不同的排序方法。 對於初學者，可以從冒泡排序或插入排序開始。 插入排序稍好一些，因為平均而言它運行得稍快一些。

Answer 3

我提議使用一種特殊集合在內部對數字進行排序，而不使用一種排序算法（例如我們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);
}