java：在数组中查找整数的频率 [英] java: Find integer's frequency in an array

问题描述

我需要开发一个 java 程序，要求用户输入一些整数并找到最大的，并且最小的数字，以及这些数字的平均值。然后，将数组分成用户指定的多个子区间，然后生成一个边界点，每个边界点的子区间宽度为...

I need to develop a java program that asks the user to enter some integers and find the largest, and smallest number, and the average of those numbers. Then, divides the set of array into a number of sub-intervals that the user specifies, then it generates a boundary points each has a length of sub-interval width..

问题是我需要创建一个频率：

The problem is that I need to create a frequency:

ex：Interval：

ex: Interval:

14.5-16.5

14.5-16.5

频率：
1（此处应显示有多少整数属于此边界）

Frequency: 1 (here it should shows how many integers belong to this boundaries)

区间：

16.5-18.5

16.5-18.5

频率： 4等等。

这是我到目前为止的代码，除了找到每个边界的频率外差不多完成..

Here is the code I have so far, almost done except finding the frequency of each boundary..

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

        int num=0;
        int range=0;
        int subnum;
        int subwid;

        System.out.print("How many numbers do you want to enter: ");
        num=input.nextInt();

        final int array[]=new int[num];

        System.out.print("Enter the numbers now: ");
        for(int i=0; i<array.length; i++)
        {
            array[i]=input.nextInt();
        }

        System.out.print("These are the numbers you entered:\n");
        printArray(array);

        int smallest=array[0];
        int largest=array[0];

        for (final int element : array) {
            if(element>largest) {
                largest=element;
            } else if(element<smallest) {
                smallest=element;
            }
            range=largest-smallest;
        }
        System.out.printf("Largest is %d\n",largest);
        System.out.printf("Smallest is %d\n",smallest);
        System.out.printf("Range is %d\n",range);

        System.out.print("Enter the number of subinterval: ");
        subnum=input.nextInt();

        subwid=range/subnum;
        System.out.printf("The width of subinterval is %d\n", subwid);

        /* this part should find the boundaries and find the elements that fall between
           the each two boundaries */
        for(double boundary=smallest-.5; boundary <=largest+.5; boundary +=subwid)
        {
        System.out.printf("Boundaries are %.1f\n",boundary);

        for(int element=0; element<array.length; element++)
          {
            if(element>=boundary)
              {
            System.out.printf("f=%d\n",element);
              }
          }
         }
    }

    public static void printArray(final int arr[])
    {

        for (final int element : arr) {
            System.out.print(element + "\n");
        }
    }

}

问题我如何找到上表中的频率？

The question is how do I find the frequencies as in the above table example ??

推荐答案

以下是一些选项：

• 嵌套循环：对于每个范围，计算该范围内的数字数。


• 'new int [ subnum]。在一次通过中，计算每个范围中的项目数。考虑使用除法和截断。


• 对数字进行排序。计算在每个边界之前出现的数量。

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