我不知道如何为bubbleSort java定义变量

Question

I am making a porgram that calculates the Mean(return as double), Median(return as double), Mode(return as int), and Standard deviation of an array that I chose myself. The most helpful things I can find are codes where the array is an input by the user.

I have been using this and some other ones similar as kind of this guide as well as my book and notes from class. Some things I just keep tinkering with them until they somehow work.

But like I said, in my code I would just like to put the array in myself and not gather input from the user. I am stuck on the median. I have it all typed up but the compiler is throwing back 1 error that says:

1 error found: File: C:\\Users\\Cori\\Desktop\\Statistics.java [line: 41] Error: The method bubbleSort(int[]) is undefined for the type Statistics

I did the bubbleSort exactly like the link says and I have been trying all kinds of crazy stuff. I think maybe It has something to do with the variable not being defined, but I really don't know because this is all very foreign to me. Here is my entire code so far. I feel like if I can just figure this out the rest of my project will be very easy.

  public class Statistics {
    public static void main(String[] args) {
        int[] a = { 22, 44, 66, 55, 33 };

        double mean;
        double median;
        median = calcMed(a);
        mean = calcMean(a);
        System.out.println("Median:" + median);
        System.out.println("Mean:" + mean);
    }

    public static double calcMean(int[] a) {
        // int[]array = {22,44,66,55,33};
        int i;// =0;
        int sum = 0;
        double mean = 0;
        for (i = 0; i < a.length; i++) {
            System.out.println(a[i]);
            sum = sum + a[i];
        }
        {
            mean = ((double) sum / ((double) a.length));
            System.out.println();
        }
        {
            return mean;
        }
    }

    // Calulate median
    public static double calcMed(int[] a) {
        int i;
        int sum = 0;
        int[] sortedArr = bubbleSort(a);

        double median = 0;
        {
            int index = (sortedArr.length - 1) / 2;
            median = sortedArr[index];
        }
        for (int v : sortedArr) {
            System.out.println(v);
        }
        return median;
    }
}

Please don't dog my formatting(just some tips would be nice). I just need to know how to fix the bubbleSort so I can calculate the median. Also I know some things are unnecessary, so if you could also give me some pointers on what is ok to delete and things that might be easier.

I figured it out.

Answer 1

You are missing the bubbleSort method (copied from the link in question):

/**
 * This program returns a sorted version of the input array.
 * 
 * @param arr
 * @return
 */
public static int[] bubbleSort(int[] arr)
{
    // We must sort the array.  We will use an algorithm called Bubble Sort.
    boolean performedSwap = true;
    int tempValue = 0;

    // If we performed a swap at some point in an iteration, this means that array
    // wasn't sorted and we need to perform another iteration
    while(performedSwap)
    {
        performedSwap = false;

        // Iterate through the array, swapping pairs that are out of order.
        // If we performed a swap, we set the "performedSwap" flag to true
        for (int i=0; i < arr.length; i++)
        {
            if (arr[i] > arr[i+1])
            {
                tempValue = arr[i];
                arr[i] = arr[i+1];
                arr[i+1] = tempValue;

                performedSwap = true;
            }
        }
    }

    return arr;
}

Without this method you can't sort the array (there are more better solutions then bubblesort, but for this case ok).
The error:

1 error found: File: C:\\Users\\Cori\\Desktop\\Statistics.java [line: 41] Error: The method bubbleSort(int[]) is undefined for the type Statistics

Tells you there is missing method bubbleSort() with parameter int[]