小编Seb*_*ebi的帖子

我注意到,一旦我的项目达到一定的大小(在我的情况下~4,100行代码),Visual Studio中的自动完成功能将无法正常工作.我还注意到,一旦第三方库的数量增加(名称空间和类属性和方法不再可见),性能也会降低.

有没有办法手动更新自动完成数据库或为现有项目创建新数据库？

我目前在Visual Studio 2008下工作,但我也在Visual Studio 2010中遇到过这个问题.

我需要计算用C#编写的代码序列的执行时间.使用DateTime.Now我得到的毫秒字段值不正确.例如:

 int start_time, elapsed_time;

 start_time = DateTime.Now.Millisecond;

 for(int i = 0; i < N_ITER; i++) {
       // cpu intensive sequence
 }

 elapsed_time = DateTime.Now.Millisecond - start_time;

elapsed_time给出负值.

我如何替换DateTime以获得经过时间的实际值？

构造函数和初始化列表之间的执行时间是否存在差异？(或者只是编码首选项的问题).我有一组需要经常创建的对象,并且想知道使用初始化列表而不是构造函数是否有任何性能提升.

如果我要创建一百万个A类实例和另一百万个B类实际选择会更好(这些对象代表网络中生成的数据包,因此这些数字).

 class A {
   private:
     int a, b;

   public:
     A(int a_var, int b_var):a(a_var), b(b_var) {}; 
 };

 class B {
   private:
     int a, b;

   public:
     B(int a_var, int b_var) {
        a = a_var;
        b = b_var;
     }
};

如果任何构造函数对于基本类型比其他构造函数更快(如示例中所示),如果a和b被类型替换,它会更快吗？

输入示例:

 class AType {
   private:
     string a, b;

   public:
     AType(string a_var, string b_var):a(a_var), b(b_var) {}; 
};

我在构建EJB会话bean 时遇到了麻烦.

packages无法找到以下内容:

import javax.ejb.LocalBean;
import javax.ejb.Stateful;
import javax.ejb.TransactionManagement; 
import javax.ejb.TransactionManagementType;

一些解决方案暗示将库j2ee.jar和javaee.jar 添加到java构建路径中.

我正在使用jdk-7u75-windows-x64,java_ee_sdk-7-windows-ml并且在给定位置找不到任何这些库($ JAVA_HOME\lib).我在Windows 7 x64机器上使用eclipse(kepler)

这个问题是一个跟进到这一个.我似乎无法在以下代码中访问jackson库:

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.fasterxml.jackson.databind.ObjectWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class ServerConfiguration {
    public String info = null;
    public String idlURL = null;
    public String idlContents = null;
    public List<ServerInfo> servers = new ArrayList<>();

    public final void clear() {
        info = null;
        idlURL = null;
        idlContents = null;
        if (servers != null)
            servers.clear();
    }

    private final static ObjectReader jsonReader;
    private final static ObjectWriter jsonWriter;

    static {
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, …

这个问题与此类似.我正在尝试 使用以下配置调试pyethapp:

入口点位于app.py中.没有被调试时代码运行正常,但是一旦我启动调试器,就抛出以下异常:

Failed to import scrypt. This is not a fatal error but does
mean that you cannot create or decrypt privkey jsons that use
scrypt

/usr/local/lib/python2.7/dist-packages/cffi/model.py:526: UserWarning: 'point_conversion_form_t' has no values explicitly defined; next version will refuse to guess which integer type it is meant to be (unsigned/signed, int/long)
  % self._get_c_name())
Traceback (most recent call last):
  File "/home/user/Utils/pycharm-community-2016.1/helpers/pydev/pydevd.py", line 1530, in <module>
    globals = debugger.run(setup['file'], None, None, is_module)
  File "/home/user/Utils/pycharm-community-2016.1/helpers/pydev/pydevd.py", line 937, …

我试图检索ELF二进制文件中的附加部分的内容.此时,我使用以下代码检索每个部分的名称:

#include <stdio.h>
#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>

#pragma pack(push,1)
#pragma pack(pop)

#define EI_NIDENT       16

/* 32-bit ELF base types. */
typedef unsigned int Elf32_Addr;
typedef unsigned short Elf32_Half;
typedef unsigned int Elf32_Off;
typedef signed int Elf32_Sword;
typedef unsigned int Elf32_Word;

/* 64-bit ELF base types. */
typedef unsigned long long Elf64_Addr;
typedef unsigned short Elf64_Half;
typedef signed short Elf64_SHalf;
typedef unsigned long long Elf64_Off;
typedef signed int Elf64_Sword;
typedef unsigned int Elf64_Word;
typedef unsigned long long Elf64_Xword;
typedef …

我遇到了一个我自己无法解决的问题,因为我刚刚开始使用JAVA FX.我得到一个令人讨厌的javafx.fxml.LoadException :,但我完全像一个向导,但我不能让我的Main运行.这是异常输出:

apr 07, 2014 4:06:37 EM application.Main start
ALLVARLIG: null
javafx.fxml.LoadException: 
/C:/Users/Jakob/Dropbox/java_kurser/Project%20Timeline/bin/application/LoginGUI.fxml

    at javafx.fxml.FXMLLoader.constructLoadException(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.load(Unknown Source)
    at application.Main.start(Main.java:21)
    at com.sun.javafx.application.LauncherImpl$8.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$7.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$6$1.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$6$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl$6.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.access$300(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$4$1.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: javax.xml.stream.XMLStreamException: ParseError …

可能重复:
GNU编译器警告"类具有虚函数但非虚析构函数"

我正在为两个类编写一个接口,我在标题中收到警告.这是代码:

class GenericSymbolGenerator {
   protected:                     // <== ok 
    ~GenericSymbolGenerator(void) {}

   public:
    virtual GenericSymbolTableCollection* generateSymbolTableCollection(GenericSymbolTableCollection *gst) = 0;
    GenericSymbolGenerator(void) {}
    // ~GenericSymbolGenerator(void) {} // <== warning if used
};

class PascalPredefinedSymbolGenerator : public GenericSymbolGenerator {
   protected:
    ~PascalPredefinedSymbolGenerator(void) {} // <== ok

   public:
    GenericSymbolTableCollection* generateSymbolTableCollection(GenericSymbolTableCollection *pst); // initializes *pst
    PascalPredefinedSymbolGenerator(void) {}
    // ~PascalPredefinedSymbolGenerator(void) {} <== warning if used
};

class PascalSymbolGenerator : public GenericSymbolGenerator {
    protected:
         ~PascalSymbolGenerator(void) {} // <== ok

    public:
     GenericSymbolTableCollection* generateSymbolTableCollection(GenericSymbolTableCollection *st); // initializes st
     PascalSymbolGenerator(void) {} …

在Solidity中,您可以使用array.length ++增加数组的大小,以便为新成员腾出空间.但我收到一个错误:

Value must be an lvalue