java - 阵列频率

Question

我正在尝试用 50 个整数值初始化一个数组，并计算 10 .. 19 范围内数字的频率。 。我认为问题出在代码的底部。

import java.util.Scanner;
public class Ex1partA {
  public static void main(String[] args) {
    Scanner kbin = new Scanner(System.in);

    int list[]=new int[50];     
    int i=0;

    System.out.print("\n\tInput numbers from 10 to 19: \n");

    while (i < 50) {
      int value = kbin.nextInt();
      if (value >= 10 & value <= 19) {
        list[i] = value;
        i++;
      } else {
        System.out.println("!! Bad number !!");
      }
    }

    for (int value : list) {
      System.out.println("" + value);
    }
  }
}

Answer 1

I'm trying to initialize an array with 50 integer values and compute the frequency of numbers in the range of 10 .. 19.

要计算频率，最好将所有数字放入 List 中，并使用 Collections.Frequency 计算频率

  List<Integer> freqList=new ArrayList<Integer>();
   // Add numebers to this list.

    for (int i = 10; i <20; i++) {
      int freq=Collections.frequency(freqList, i);
                      // This will return frequency of number

        System.out.println(i+"  "+freq);  
    }