我在互联网上找到了这个代码，它是用于数组的，我想将它改为双向链表（而不是索引，我们应该使用指针），请你帮我一下，我该如何改变合并方法（我改变了排序方法由我自己）也这不是我的家庭工作，我喜欢与链接列表工作！ public class MergeSort { private DoublyLinkedList LocalDoublyLinkedList; public MergeSort(DoublyLinkedList list) { LocalDoublyLinkedList = list; } public void sort() { if (LocalDoubl
我在互联网上找到了这个代码，它是用于数组的，我想将它改为双向链表（而不是索引，我们应该使用指针），请你帮我一下，我该如何改变合并方法（我改变了排序方法由我自己）也这不是我的家庭工作，我喜欢与链接列表工作！ public class MergeSort { private DoublyLinkedList LocalDoublyLinkedList; public MergeSort(DoublyLinkedList list) { LocalDoublyLinkedList = list; } public void sort() { if (LocalDoubl
I just stumbled upon something. At first I thought it might be a case of branch misprediction like it is in this case, but I cannot explain why branch misprediction should cause this phenomenon. I implemented two versions of Bubble Sort in Java and did some performance tests: import java.util.Random; public class BubbleSortAnnomaly { public static void main(String... args) { fina
我只是偶然发现了一些事情。 起初我认为这可能是一个分支预测失误的情况，就像在这种情况下一样，但我无法解释为什么分支预测失误会导致这种现象。 我在Java中实现了两个版本的Bubble Sort，并进行了一些性能测试： import java.util.Random; public class BubbleSortAnnomaly { public static void main(String... args) { final int ARRAY_SIZE = Integer.parseInt(args[0]); final int LIMIT = Integ
I have heard a teacher drop this once, and it has been bugging me ever since. Let's say we want to check if the integer x is bigger than or equal to 0. There are two ways to check this: if (x > -1){ //do stuff } and if (x >= 0){ //do stuff } According to this teacher > would be slightly faster then >= . In this case it was Java, but according to him this also applie
我听说有一位老师放弃了这一次，从那以后一直困扰着我。 假设我们想检查整数x是否大于或等于0.有两种方法可以检查： if (x > -1){ //do stuff } 和 if (x >= 0){ //do stuff } 根据这位老师， >会稍快，那么>= 。 在这种情况下，它是Java，但根据他的说法，这也适用于C，C ++和其他语言。 这个陈述有没有道理？ 在任何现实世界中都没有区别。 让我们来看看各种编译器为不同目标生成的代码。
Here is a piece of C++ code that seems very peculiar. For some strange reason, sorting the data miraculously makes the code almost six times faster. #include <algorithm> #include <ctime> #include <iostream> int main() { // Generate data const unsigned arraySize = 32768; int data[arraySize]; for (unsigned c = 0; c < arraySize; ++c) data[c] = std::ra
这是一段C ++代码，看起来很奇特。 出于某种奇怪的原因，对数据进行奇迹排序使得代码几乎快了六倍。 #include <algorithm> #include <ctime> #include <iostream> int main() { // Generate data const unsigned arraySize = 32768; int data[arraySize]; for (unsigned c = 0; c < arraySize; ++c) data[c] = std::rand() % 256; // !!! With this, the next loop runs f
Lets say I have a object foo from class Foo . Lets say class Foo has a lot of fields that characterize its offsprings. When having so many fields, is it preferred to initialize them all via the constructor of Foo eg. Foo foo = new Foo(0, 12, 123, 2, 2, (and so on...)); or initialize them in the constructor or method from the class one will be using foo eg. Foo foo = new Foo(); public void
可以说我有一个Foo类的对象foo 。 可以说Foo班有很多描述其后代特征的领域。 当有这么多的字段时，是否最好通过Foo的构造函数来初始化它们。 Foo foo = new Foo(0, 12, 123, 2, 2, (and so on...)); 或者在类的构造函数或方法中使用foo来初始化它们。 Foo foo = new Foo(); public void initFoo() { foo.setX(1); foo.setY(3); foo.setH(3); (and so on...) } 我会尽全力通过构造函数。 这样，你不能忘
Let's look at the simple Java code in the following snippet: public class Main { private int temp() { return true ? null : 0; // No compiler error - the compiler allows a return value of null // in a method signature that returns an int. } private int same() { if (true) { return null; // The same is not possible with if,
让我们看看下面代码片段中的简单Java代码： public class Main { private int temp() { return true ? null : 0; // No compiler error - the compiler allows a return value of null // in a method signature that returns an int. } private int same() { if (true) { return null; // The same is not possible with if, // and causes
I've just started with android development and updating the UI is really bugging me :/ This is what I've got working so far - package projects.Move; import android.os.Bundle; import android.view.View; import android.app.Activity; import android.content.Context; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Color; public class Move extends Ac
我刚刚开始使用android开发并更新UI真的让我感到困扰：/ 这是我迄今为止的工作 - package projects.Move; import android.os.Bundle; import android.view.View; import android.app.Activity; import android.content.Context; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Color; public class Move extends Activity { private float y = 0; private long now =
I'm just learning some basics of Java and have little problem with my app This is part of my MainActivity @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); FloatingActionButton button = (FloatingA
我只是学习了一些Java的基础知识，并且对我的应用程序没有什么问题 这是我的MainActivity的一部分 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); FloatingActionButton button = (FloatingActionButton) findV
This is my activity class,where I have spinner.I need to load the database values to the spinner,So Using ArrayList and ArrayAdapter,I did that. But when I run my app,It's giving Null pointer exception. public class addexpense extends ActionBarActivity { DBhelper helper; SQLiteDatabase db; Spinner spinner; @Override /** Called when the activity is first created. */
这是我的活动类，我有spinner.I需要加载数据库值到微调，所以使用ArrayList和ArrayAdapter，我做到了。 但是当我运行我的应用程序时，它提供了Null指针异常。 public class addexpense extends ActionBarActivity { DBhelper helper; SQLiteDatabase db; Spinner spinner; @Override /** Called when the activity is first created. */ protected void onCreate(Bundle savedInstanceState) {
I haven't finished this app, but I was hoping to see what it looks like on my phone. However, it force-closes with an InstantiationException. Exception in logcat: 09-19 20:13:47.987: D/szipinf(5396): Initializing inflate state 09-19 20:13:48.007: D/dalvikvm(5396): newInstance failed: no () 09-19 20:13:48.007: D/AndroidRuntime(5396): Shutting down VM 09-19 20:13:48.007: W/dalvikvm(5396):
我还没有完成这个应用程序，但我希望看到我的手机上看起来像什么。 但是，它强制关闭一个InstantiationException。 logcat中的异常： 09-19 20：13：47.987：D / szipinf（5396）：初始化膨胀状态09-19 20：13：48.007：D / dalvikvm（5396）：newInstance失败：no（）09-19 20：13：48.007： D / AndroidRuntime（5396）：关闭VM 09-19 20：13：48.007：W / dalvikvm（5396）：threadid = 1：线程退出时未捕获的异常（grou