滚动你自己的std :: vector ??? [英] Roll your own std::vector ???

问题描述

我需要几个自定义类的std :: vector like功能。我已经在没有Boxing的名为ArrayList的线程中广泛讨论了这个问题，并且

拆箱。解决方案是为每个自定义类创建非泛型（非C ++模板）

std :: vector like功能。 （解决方案必须

在Visual Studio 2002中工作）。


因为我已经为YeOlde C ++编译器编写了一个std :: vector（Borland

C ++ 1.0）既没有模板也没有STL，我知道怎么做。我不知道怎么做才能直接在垃圾收集的C＃中重新分配内存。


我写了我需要的东西伪代码，

的正确C＃语法是什么？


int size;

int容量;


bool AppendDataItem（DataItemType Data）{

if（size == Capacity）{

（1）Capacity = Capacity * 2; //或* 1.5

（2）Temp = MemoryPointer;

（3）MemoryPointer =分配（容量）;

（4）复制从Temp到MemoryPointer的数据;

（5）DeAllocate（Temp）;

（6）MemoryPointer [Size] =数据;

（7 ）尺寸++;

}

}

解决方案

" Peter Olcott" ; < No **** @SeeScreen.comaécritdansle message de news：

wJ*******************@newsfe18.lga ...


|我需要std :: vector类似于几个自定义类的功能。


|我已经写了我需要的伪代码，什么是正确的C＃语法

for

|这个？


在C＃中，通常不应手动释放内存，因为这会降低

GC的速度。


如果你真的不能或不想使用通用List< Tclass，那么

会更快更容易，那么试试这段代码，我认为它实现了你的目标>
想要：


公共课测试

{

private int size = 0;


int [] ia = new int [4];


public void AppendDataItem（int data）

{

if（size == ia.Length）

Array.Resize（ref ia，ia.Length * 2）;


ia [size ++ ] =数据;

}

}

{

测试t =新测试（）;


for（int i = 0; i< 10; i ++）

t.AppendDataItem（i）;

}


Joanna


-

Joanna Carter [TeamB]

顾问软件工程师

" Joanna Carter [TeamB]" < jo **** @not.for.spamaécritdansle message de

news： ee ************** @ TK2MSFTNGP04.phx.gbl ...


|如果你真的不能或不想使用通用List< Tclass，那么

|会更快更容易，然后尝试这个代码，我认为它实现了什么

你

|想：


对不起，我使用了只在.NET 2.0中提供的array.Resize（...）;你好

说你想要.NET 1兼容性，之前你需要使用Copy或

CopyTo：


|公共课测试

| {

| private int size = 0;

|

| int [] ia = new int [4];

|

| public void AppendDataItem（int data）

| {

if（size == ia.Length）

{

int [] temp = new int [ia.Length * 2];


Array.Copy（ia，temp，ia.Length）;


ia = temp;

}


ia [size ++] =数据;

| }

| }


Joanna


-

Joanna Carter [TeamB]

顾问软件工程师

" Joanna Carter [TeamB]" < jo **** @ not.for.spamwrote in message

news：％2 *************** @ TK2MSFTNGP06.phx.gbl .. 。

" Joanna Carter [TeamB]" < jo **** @not.for.spamaécritdansle message de

news： ee ************** @ TK2MSFTNGP04.phx.gbl ...


|如果你真的不能或不想使用通用List< Tclass，那么

|会更快更容易，然后尝试这个代码，我认为它实现了什么

你

|想：


对不起，我使用了只在.NET 2.0中提供的array.Resize（...）;你好

说你想要.NET 1兼容性，之前你需要使用Copy或

CopyTo：


|公共课测试

| {

| private int size = 0;

|

| int [] ia = new int [4];

我假设你在这里分配四个整数，并且我可以轻松地分配一个整数。
< blockquote class =post_quotes>
|

| public void AppendDataItem（int data）

| {

if（size == ia.Length）

{

int [] temp = new int [ia.Length * 2];


Array.Copy（ia，temp，ia.Length）;

如果我理解正确的话，我们可以使用

这个陈述来改善性能：

Array.Copy（ia，temp，size）;

我说错了吗？ （目的地，来源，长度）???

>

ia = temp;

这就像C ++中的指针赋值???

}


ia [size ++] = data;

| }

| }


Joanna


-

Joanna Carter [TeamB]

顾问软件工程师

I need std::vector like capability for several custom classes. I already
discussed this extensively in the thread named ArrayList without Boxing and
Unboxing. The solution was to simply create non-generic (non C++ template)
std::vector like capability for each of these custom classes. (Solution must
work in Visual Studio 2002).

Since I have already written one std::vector for a YeOlde C++ compiler (Borland
C++ 1.0) that had neither templates nor STL, I know how to do this. What I don''t
know how to do is to directly re-allocate memory in the garbage collected C#.

I have written what I need in pseudocode, what is the correct C# syntax for
this?

int Size;
int Capacity;

bool AppendDataItem(DataItemType Data) {
if (Size == Capacity) {
(1) Capacity = Capacity * 2; // Or * 1.5
(2) Temp = MemoryPointer;
(3) MemoryPointer = Allocate(Capacity);
(4) Copy Data from Temp to MemoryPointer;
(5) DeAllocate(Temp);
(6) MemoryPointer[Size] = Data;
(7) Size++;
}
}

解决方案

"Peter Olcott" <No****@SeeScreen.coma écrit dans le message de news:
wJ*******************@newsfe18.lga...

|I need std::vector like capability for several custom classes.

| I have written what I need in pseudocode, what is the correct C# syntax
for
| this?

In C#, should not normally deallocate memory manually as this slows down the
GC.

If you really can''t or don''t want to use the generic List<Tclass, which
would be faster and easier, then try this code, I think it achieves what you
want :

public class Test
{
private int size = 0;

int[] ia = new int[4];

public void AppendDataItem(int data)
{
if (size == ia.Length)
Array.Resize(ref ia, ia.Length * 2);

ia[size++] = data;
}
}
{
Test t = new Test();

for (int i = 0; i < 10; i++ )
t.AppendDataItem(i);
}

Joanna

--
Joanna Carter [TeamB]
Consultant Software Engineer

"Joanna Carter [TeamB]" <jo****@not.for.spama écrit dans le message de
news: ee**************@TK2MSFTNGP04.phx.gbl...

| If you really can''t or don''t want to use the generic List<Tclass, which
| would be faster and easier, then try this code, I think it achieves what
you
| want :

Sorry, I used array.Resize(...) which is only available in .NET 2.0; you
said you wanted .NET 1 compatibilty, thyerefore you need to use Copy or
CopyTo :

| public class Test
| {
| private int size = 0;
|
| int[] ia = new int[4];
|
| public void AppendDataItem(int data)
| {
if (size == ia.Length)
{
int[] temp = new int[ia.Length * 2];

Array.Copy(ia, temp, ia.Length);

ia = temp;
}

ia[size++] = data;
| }
| }

Joanna

--
Joanna Carter [TeamB]
Consultant Software Engineer

"Joanna Carter [TeamB]" <jo****@not.for.spamwrote in message
news:%2***************@TK2MSFTNGP06.phx.gbl...

"Joanna Carter [TeamB]" <jo****@not.for.spama écrit dans le message de
news: ee**************@TK2MSFTNGP04.phx.gbl...

| If you really can''t or don''t want to use the generic List<Tclass, which
| would be faster and easier, then try this code, I think it achieves what
you
| want :

Sorry, I used array.Resize(...) which is only available in .NET 2.0; you
said you wanted .NET 1 compatibilty, thyerefore you need to use Copy or
CopyTo :

| public class Test
| {
| private int size = 0;
|
| int[] ia = new int[4];

I am assuming that you are allocating four integers here, and that I could just
as easily allocate one.

|
| public void AppendDataItem(int data)
| {
if (size == ia.Length)
{
int[] temp = new int[ia.Length * 2];

Array.Copy(ia, temp, ia.Length);

If I understand this correctly, we could improve the performance a little using
this statement instead:
Array.Copy(ia, temp, size);
Am I correct? (Destination, Source, Length) ???

>
ia = temp;

Is this like a pointer assignment in C++ ???

}

ia[size++] = data;
| }
| }

Joanna

--
Joanna Carter [TeamB]
Consultant Software Engineer

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