java - Java中的getInteger

我是Java的新手。我了解了基础知识，但没有，但是仍然对基本代码有一些麻烦。无论如何，我编写了这段代码，但是由于不知道如何将其放入代码中而遇到了两个错误。有人可以向我解释如何getInteger或如何在我的代码中应用它吗？

我知道如何进行用户输入的唯一方法是使用Java中的Scanner。不是这种方式。这是教授要我使用的主要方法，所以我无法编辑主要方法。它可能很简单，但是我很迷茫，似乎无法正常工作。

class ArrayIns1
{
    private long[] theArray;
    private int nElems;
    public int numCounts;

    public ArrayIns1(int max) {
        theArray = new long[max];
        nElems = 0;
    }

    public void insert(long value) {
        theArray[nElems] = value;
        nElems++;
    }

    public void display() {
        System.out.print("A= ");
        for (int j = 0; j < nElems; j++)
            System.out.print(theArray[j] + " ");
        System.out.println("");
    }

    public void quickSort() {
        recQuickSort(0, nElems - 1);
    }

    public void recQuickSort(int left, int right) {
        int size = right - left + 1;

        if (size <= 3)
            manualSort(left, right);
        else {
            long median = medianOf3(left, right);
            int partition = partitionIt(left, right, median);

            recQuickSort(left, partition - 1);
            recQuickSort(partition + 1, right);
        }
    }

    public long callSelection(int ind) {
        return recSelect(0, nElems - 1, ind - 1);
    }

    public long recSelect(int left, int right, int index) {
        int size = right - left + 1;
        if (size <= 3) {
            manualSort(left, right);

            return theArray[index];
        }

        long median = medianOf3(left, right);
        int partition = partitionIt(left, right, median);

        if (partition == index)
            return theArray[index];
        else if (index < partition)
            return recSelect(left, partition - 1, index);
        else
            return recSelect(partition + 1, right, index);
    }

    public long medianOf3(int left, int right) {
        int center = (left + right) / 2;

        if (theArray[left] > theArray[center]) {
            swap(left, center);
        }

        if (theArray[left] > theArray[right]) {
            swap(left, right);
        }

        if (theArray[center] > theArray[right]) {
            swap(center, right);
        }

        swap(center, right - 1);

        return theArray[right - 1];
    }

    public void swap(int dex1, int dex2)
    {
        long temp = theArray[dex1];
        theArray[dex1] = theArray[dex2];
        theArray[dex2] = temp;

        numCounts += 3;
    }

    /*
     * This is the main partition function .
     */
    public int partitionIt(int left, int right, long pivot)
    {
        int leftPtr = left;
        int rightPtr = right - 1;

        while (true)
        {
            while (theArray[++leftPtr] < pivot)
                numCounts++;

            while (theArray[--rightPtr] > pivot)
                numCounts++;

            if (leftPtr >= rightPtr)
            {
                numCounts++;
                break;
            }
            else
                swap(leftPtr, rightPtr);
        }

        swap(leftPtr, right - 1);

        return leftPtr;
    }

    public void manualSort(int left, int right)
    {
        int size = right - left + 1;

        if (size <= 1)
            return;

        if (size == 2)
        {
            if (theArray[left] > theArray[right])
            {
                numCounts++;
                swap(left, right);
            }
            return;
        }
        else
        {
            if (theArray[left] > theArray[right - 1])
            {
                numCounts++;
                swap(left, right - 1);
            }

            if (theArray[left] > theArray[right])
            {
                numCounts++;
                swap(left, right);
            }

            if (theArray[right - 1] > theArray[right])
            {
                numCounts++;
                swap(right - 1, right);
            }
        }
    }
}

class pp74
{
    public static void main(String[] args) {
        int maxSize = 7; // array size
        int k = 0; // arbitrary index

        ArrayIns arr; // reference to array
        arr = new ArrayIns(maxSize); // create array

        for (int j = 0; j < maxSize; j++) // fill array with
        { // random numbers
            long n = (int)(java.lang.Math.random() * 99);
            arr.insert(n);
        }
        arr.display(); // display array
        // get k from user
        System.out.print("Enter k (smallest is 1): ");
        k = getInteger();

        // get value of k-th elem
        long value = arr.recSelect(0, maxSize - 1, k - 1);
        // print value
        System.out.println("Value of " + k + "the element is " + value);
        arr.display();
    } // end main()
}

错误：

error: cannot find symbol
       k = getInteger();
            ^
    symbol:   method getInteger()
    location: class pp74
1 errors

最佳答案

您的代码注释显示您要从用户读取integer的k值，
如果是这样，则使用下面的代码

import java.util.Scanner;
..
..
// get k from user
System.out.print("Enter k (smallest is 1): ");
Scanner in = new Scanner(System.in);
int k = in.nextInt();

并创建ArrayIns1而不是ArrayIns的对象