小编use*_*491的帖子

基本上如果我有一个数组

String[] animals = {"dog", "cat", "pig"}

我想制作一个数组

String[] animals2 = {"dog", "cat", "pig", x} 

其中x是任意的

编辑:我知道ArrayList在这里会更好,但是它用于作业,它要求我使用数组.

再次编辑:我知道这不是最简单的因为我不能使用ArrayList或Arrays,但我想出了解决方案:

String[] name2 = new String[name.length + 1];
    for(int i = 0; i < name.length; i++)
    {
        name2[i] = name[i];
    }
    for (int k = name2.length - 1; k >= pos; k--)
    {
        name2[k] = name2[k - 1];
    }
    name2[pos - 1] = canName;

我需要帮助来编写我的插入排序,它插入点pos.谢谢你的帮助.

我收到一个错误,指出"无法找到方法 - getCenter"但是每当我用"a,b或d"这样的单个对象替换"objects.get(i)"时,它就会发现方法很好.我不明白为什么它无法从ArrayList中找到该方法.

public class TestPoly
{
public static void main (String []args)
{
    ArrayList objects = new ArrayList();

    Circle2 a = new Circle2(33,10,4);
    Cylinder2 b = new Cylinder2(21,15,40,5);
    Oval2 c = new Oval2(3,7,34,10);
    OvalCylinder2 d = new OvalCylinder2(5,11,5,5,7);

    objects.add(a);
    objects.add(b);
    objects.add(c);
    objects.add(d);

    for (int i = 0; i < objects.size(); i++)
    {
        System.out.println("For " + objects.get(i).getClass().getName() + objects.get(i).getCenter());
    }
}
}

Circle2就是这个.

public class Circle2
{
// instance variables 
private int x;
private int y;
private int radius;

/** …

cannot find symbol - variable minDist即使我知道它已被声明并初始化,我仍然会收到此错误.我觉得它直接盯着我的脸.有谁知道为什么会这样？

还有另一个类文件,但我不认为错误在那里.

我得到它的倒数第三行,当我去minDist,但如果我删除minDist我也得到它minCost,并minMPG为好.

public class AnnualFuelUseTester
{
    public static void main(String[] args)
    {
    int sMiles1, sMiles2, sMiles3, sMiles4;
    int eMiles1, eMiles2, eMiles3, eMiles4;
    int[] dist = new int[4];
    double gals1, gals2, gals3, gals4;
    double[] MPG = new double[4];
    double price1, price2, price3, price4;
    double[] cost = new double[4];

    AnnualFuelUse[] fillUps = {new AnnualFuelUse(108438, 108725, 13.9, 2.98),
                               new AnnualFuelUse(108738, 109023, 15.3, 3.02),
                               new AnnualFuelUse(109023, 109232, 10.3, 3.05), …

这可能是一个相当简单的问题.我只是无法弄清楚如何按降序而不是升序进行排序.谁能帮我吗？

public static void sortYear(Movie4[] movies, int low, int high)
{
    if ( low == high ) 
        return; 
    int mid = ( low + high ) / 2; 
    sortYear( movies, low, mid ); 
    sortYear( movies, mid + 1, high ); 

    mergeYears(movies, low, mid, high ); 
}

public static void mergeYears(Movie4[] movies, int low, int mid, int high)
{

    Movie4[] temp = new Movie4[ high - low + 1 ]; 
    int i = low, j = mid + 1, n = …