C ++模板参数化构造函数 [英] C++ Templates parameterized constructor

问题描述

你好，
我是C ++模板的新手，并且在将c#代码移植到c ++时遇到问题

我想创建一个可以容纳任何类型的循环缓冲区，因此需要模板.

在C#中，我有这个(简化代码)

Hello,
I''m new to templates in C++ and I''m having issues to port my c# code to c++

I want to create a circular buffer which can hold any type thus a template is required.

In c# I have this (simplified code)

public class buffer<T>;
{
	private T[] items;
	
	public buffer(int size)
	{
		items = new T[size];
	}
}

也很容易使用:

also it''s easy to use:

buffer<int> buf = new buffer<int>(10);

这将根据类型为int的缓冲区创建一个长度为10的缓冲区...

无论如何，所以现在我在将其移植到不受管理的c ++时遇到问题.
我已经阅读了一些有关c ++模板的教程，以获得某种理解，但是到目前为止，我还无法解决这个问题.这可能很简单，但是语法不同(我猜是这样).

所以到目前为止我的C ++代码:
标头:

That creates a buffer from the type int that will be 10 long...

Anyway, so now I''m having problems porting this to unmanaged c++.
I''ve read a couple of tutorials on templates in c++ to get some sort of understanding, but I''m not able to work this out so far. It''s probably very easy, but just a different syntax (I guess).

So my C++ code so far:
header:

template <class T>
class buffer {
public:
	buffer(unsigned int size);
private:
	T* items;
}

源文件:

source file:

template <class T>
buffer<t>::buffer(unsigned int size)
{
	items = new T[size];
}</t>

可以正确编译，但是我现在知道如何创建新缓冲区...

this compiles correctly, but I have now idea how to create a new buffer...

buffer<int> buf;

不能正常工作，我想出的其他东西也不能正常工作.

谁能告诉我如何以一种整洁的方式解决此问题:)

is not working, neither is the rest of what I came up with.

Can anybody tell me how to fix this in a neat way :)
Thanks in advance!

推荐答案

首先，不要为模板代码使用单独的源文件-将其放在头文件中:

First, don''t use a separate source file for your template code - put it in the header file:

template <class T>
class buffer {
public:
    buffer(unsigned int size)
    {
        items = new T[size];
    }
private:
    T* items;
};

没有定义默认的构造函数，因此在实例化类时需要提供大小:

There is no default constructor defined, so you need to supply the size when instantiating the class:

buffer<int> buf(10);

...并且不要忘记在delete [] items的生命周期末尾添加析构函数.

...and don''t forget to add a destructor to delete [] items at the end of its lifetime.

//C++_Class_Templates.cpp

#include <iostream.h>
#include <vector>

template <typename t>
class MyQueue
{
     std::vector<t> data; 
   public:
     void Add(T const &);
     void Remove();
     void Print();
};

template <typename t> void MyQueue<t> ::Add(T const &d)
{
     data.push_back(d);
}

template <typename t> void MyQueue<t>::Remove()
{
     data.erase(data.begin( ) + 0,data.begin( ) + 1);
}

template <typename t> void MyQueue<t>::Print()
{
     std::vector<int>::iterator It1;
     It1 = data.begin();
     for ( It1 = data.begin( ) ; It1 != data.end( ) ; It1++ )
        cout << " " << *It1<<endl;

}
//Usage for C++ class templates
void main()
{
     MyQueue<int> q;
     q.Add(1);
     q.Add(2);

     cout<<"Before removing data"<<endl;
     q.Print();

     q.Remove();
     cout<<"After removing data"<<endl;
     q.Print();
}

我认为这页面 [ ^ ]将有助于对其进行解释.

I think this page[^] will help to explain it.

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