C ++重载运算符=指针无法正常工作/编译 [英] C++ Overload Operator = for Pointers does not work/compile properly

问题描述

我正在尝试使用=的运算符重载来实现模板类 到目前为止，它适用于非指针元素.对于Pointer Elements，它不能完全按我的预期工作，所以我的问题是为什么要播种，以及如何强制c ++按我的意愿进行操作.

I am trying to implement a template Class with an Operator Overload for = so far it works for non pointer elements. For Pointer Elements it doesn't work exactly as I expect it to, so my question is why this is sow and how do I force c++ do it as I want.

我的模板类:

template <class T>
class IBag {
public:
    T _val;
    void Set(T val) { _val = val; } 
    T Get() { return _val; }

    IBag& operator=(T val) {
        this->Set(val);
        return *this;
    }

    operator T() {
        return this->Get();
    }
};

使用IBag类如何工作:

How it works using the IBag Class:

class IBagExample
{
   void showExample() {
        IBag<QString*> pbag;
        pbag = new QString("Blub"); // This works !
    }
};

它如何不编译:

class IBagExample
{
   void showExample() {
        IBag<QString*> pbag = new QString("Blub"); // This doesn't compile !
    }
};

我得到的编译器错误是:

The compiler Error I get is :

error: no viable conversion from 'QString *' to 'IBag<QString *>'
    IBag<QString*> pbag2 = new QString("Blub");
                   ^       ~~~~~~~~~~~~~~~~~~~

对我来说似乎是相同的，也许我需要告诉编译器一些信息，以了解现在将哪种类型的指针推入pbag中.但是我不知道该怎么做.

For me it seems the same, maybe I need to tell the compiler something to understand what type of pointer is now going to be pushed into the pbag. But I have no Idea how to do that.

使用像

IBag<QString*> pbag; pbag = new QString("Blub"); // This does compile !

似乎太荒谬了.

(注意:IBag示例只是我要实现的代码的简化.)

(Note:The IBag example is just a simplification of the Code I am trying to implement.)

非常感谢

推荐答案

IBag<QString*> pbag = new QString("Blub");

这实际上没有调用赋值运算符，而是调用了构造函数.您需要定义如下内容:

This doesn't actually call the assignment operator, it calls a constructor. You need to define that something like:

template <class T>
class IBag {
public:
    IBag( const IBag& rhs )
    {
        // ....
    }

};

或:

    IBag( const T& rhs )
    {
        // ....
    }

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