计算数组中显示了多少个整数

Question

我有一个包含 100 个随机元素的数组，每个元素的范围是 0-10，我需要计算每个整数被输入了多少次（例如 1,2,2,3,8,8， 4...)

输出：

1 - 1

2 - 2

3 - 1

8 - 2

4 - 1

到目前为止我的代码是：

import java.util.Random;

public class Asses1 {
    public static void main(String[] args) {

        getNumbers();
      }

    private static int randInt() {
        int max = 10;
        int min = 0;

        Random rand = new Random();

        int randomNum = rand.nextInt((max - min) + 1) + min;
        return randomNum;
    }

    public static int[] getNumbers() {
        int number = 100;
        int[] array = new int[number];
        for (int i = 0; i < array.length; i++) {
            System.out.println(randInt());
        }

        System.out.println(number+" random numbers were displayed");
        return array;
    }

}

Answer 1

int[] array2 = new int[11];

for (int i = 0; i < array.length; i++){
    array2[randInt()]++
}
for (int i = 0; i < array.length; i++)
    System.out.println(String.valueOf(i) + " - " + String.valueOf(array2[i]));

我所做的是：

创建一个帮助数组 array2 用于存储每个数字的出现次数。
生成数字时会增加帮助数组中出现的次数。

Answer 2

添加这个方法，它将进行计数：

public static void count(int[] x) {
    int[] c=new int[11];

    for(int i=0; i<x.length; i++)
        c[x[i]]++;

    for(int i=0; i<c.length; i++)
        System.out.println(i+" - "+c[i]);
}

并将 main 更改为这样，以便您调用之前的方法：

public static void main(String[] args) {

    count(getNumbers());
  }

此外，将 getNumbers 中的 for 循环更改为这样，以便用生成的数字填充 array，而不仅仅是打印它们：

    for (int i = 0; i < array.length; i++) {
        array[i] = randInt();
        System.out.println(array[i]);
    }

Answer 3

这是在 java 8

中如何完成的

// Retrieve the random generated numbers
int[] numbers = getNumbers();
// Create an array of counters of size 11 as your values go from 0 to 10
// which means 11 different possible values.
int[] counters = new int[11];
// Iterate over the generated numbers and for each number increment 
// the counter that matches with the number
Arrays.stream(numbers).forEach(value -> counters[value]++);
// Print the content of my array of counters
System.out.println(Arrays.toString(counters));

输出：

[12, 11, 7, 6, 9, 12, 8, 8, 10, 9, 8]

注意： 您的方法 getNumbers 不正确，您应该按以下方式修复它：

public static int[] getNumbers() {
    int number = 100;
    int[] array = new int[number];
    for (int i = 0; i < array.length; i++) {
        array[i] = randInt();
    }

    System.out.println(number+" random numbers were displayed");
    return array;
}

Answer 4

Map<Integer,Integer> map=new HashMap<Integer,Integer>();
        int temp;
        for (int i = 0; i < array.length; i++) {
            temp=randInt();
            if(map.containsKey(temp)){
                map.put(temp, map.get(temp)+1);
            }else{
                map.put(temp, 1);
            }
        }

计算数组中显示了多少个整数

Count how many integers were displayed in an array

java

arrays

element

count