java - 了解 equals 方法的模式和帮助

Question

我有 2 个简单问题；这是我的代码。我对该模式方法的工作原理感到困惑(它有效)。我还需要有关 equals 方法的帮助。我是否只需创建另一个数组并查看它们是否相等，我该怎么做？

Public class Grades
{
    private int[] grade;
    private int highest, mode;
    private double average, median;

    public Grades(int n)
    {
        Random r = new Random();
        grade = new int[n];
        for (int i = 0; i < n; i++)
            grade[i] = Math.abs(r.nextInt())%101;
    }

    public double getTotal()
    {
        int total = 0;
        int i;
        for (i = 0; i < grade.length; i++)
            total += grade[i];
        return total;
    }

    public void calAverage()
    {
        average = getTotal()/(double) grade.length;
    }

    public int getHigh()
    {
        return highest;
    }

    public double getMedian()
    {
        return median;
    }

    public int getMode()
    {
        return mode;
    }

    public double getAverage()
    {
        return average;
    }

    public void highest()
    {
        highest = grade[grade.length - 1];
    }

    public void sort()
    {

        int i, j, t;
        for (i = 0; i < grade.length - 1; i++)
            for (j = i + 1; j < grade.length; j++)
                if (grade[i] > grade[j])
                {
                    t = grade[i];
                    grade[i] = grade[j];
                    grade[j] = t;
                }
    }

    public void calMedian()
    {

        if (grade.length%2 == 0)
            median = (grade[grade.length/2 - 1] + grade[(grade.length)/2])/2.;
        else
            median = grade[grade.length/2];
    }

    public void calMode()
    {
        int[] a = new int[101];
        int i, m;
        for (i = 0; i <= grade.length; i++)
            a[i] = 0;
        for (i = 0; i < grade.length; i++)
            a[grade[i]]++;
        m = 0;
        for (i = 0; i < a.length; i++)
            if (a[i] > a[m])
                m = i;
        mode = m;
    }

    public String toString()
    {
        int i;
        String s = "";
        for (i = 0; i < grade.length; i++)
        {
            s = s + grade[i] + " ";
            if ((i + 1)%10 == 0)
                s = s + '\n';
        }
        return s;
    }

}

Answer 1

我已经解释了 mode() 方法，但我不确定您对 equals() 方法有何要求，如果您能澄清，我将更新我的答案以包括对此的解释。

public void calMode()
{
    // This array will allow for indexes from 0 to 100 
    // (the same range as a grade on a 0-100 scale)
    int []a=new int[101];

    int i,m; // these are just temporary indexes

    // You don't need to do this, an int in java is set to 0 by default
    // as is an array of ints
    for(i=0;i<=grade.length;i++) 
         a[i]=0;

    // Here you are looking at each grade and incrementing the occurrences of each
    // where each index is the grade and the value stored at that index is the number
    // of times that grade appears
    for(i=0;i<grade.length;i++)
        a[grade[i]]++;
    m=0;

    // Here you are finding which grade has the highest frequency (the mode)
    // by comparing the values you calculated in the previous loop
    for(i=0;i<a.length;i++)
        if(a[i]>a[m])
            m=i;
        mode=m;
}