blocks|key|2139053|text|my_adult是一个指针，而hand不是，简单明了。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2139054|您需要：|2139055|class+Child
{
private:
+Adult+my_adult;+//no+pointer

public:
+Child();
+Child(Adult+&hand){
++my_adult+=+hand;
+}
};|code-block|syntax|javascript|2139056|或|2139057|class+Child
{
private:
+Adult*+my_adult;

public:
+Child();
+Child(Adult*+hand){+//pointer+parameter
++my_adult+=+hand;
+}
};|2139058|你的第一个例子也是非法的：|2139059|child+=+new+Child(this);|2139060|不应该编译，因为孩子是一个对象，而不是一个指针。|2139061|child+=+Child(this);|2139062|才是正确的版本。|2139063|entityMap^0|0|8|F|4|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|17|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|19|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|1A|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1B|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|1C|8|@]|D|@]|E|$K|L]]|$1|U|3|V|5|6|7|1D|8|@]|D|@]|E|$]]|$1|W|3|X|5|J|7|1E|8|@]|D|@]|E|$K|L]]|$1|Y|3|Z|5|6|7|1F|8|@]|D|@]|E|$]]|$1|10|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]]|11|$]]

<code>my_adult</code> is a pointer, <code>hand</code> is not, pure and simple. 

You either need:

<pre><code>class Child
{
private:
 Adult my_adult; //no pointer

public:
 Child();
 Child(Adult &amp;hand){
 my_adult = hand;
 }
};
</code></pre>

or

<pre><code>class Child
{
private:
 Adult* my_adult;

public:
 Child();
 Child(Adult* hand){ //pointer parameter
 my_adult = hand;
 }
};
</code></pre>

Your first example is also illegal:

<pre><code>child = new Child(this);
</code></pre>

shouldn't compile, since child is an object, not a pointer.

<pre><code>child = Child(this);
</code></pre>

would be the correct version.

blocks|key|128240|text|地址和*类型指针是一回事。更改子构造函数以获取Adult*，并使用初始化语法而不是=对其进行初始化|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|128241|Child(Adult*+hand):+my_adult(hand)+{+}+|code-block|syntax|javascript|128242|一旦你有了这个指针，你的子类中的代码就可以根据需要调用my_adult->Whatever()。您需要知道，只有在Adult对象总是比Child对象存活时间长的情况下，这种方法才是安全的。例如，如果一个订单被删除，所有的订单项也会被删除，所以你不需要担心一个订单项使用了一个指向它的订单的无效指针。如果你的系统中不是这样，那么你有一个比指针语法更大的问题要担心。|128243|entityMap^0|N|6|15|1|0|0|R|K|1L|5|1V|5|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$]]

An address and a * type pointer are the same thing. Change your Child constructor to take an <code>Adult*</code> and initialize it with initialization syntax, not an <code>=</code>:

<pre><code>Child(Adult* hand): my_adult(hand) { } 
</code></pre>

Once you have that pointer, code in your Child class can call <code>my_adult-&gt;Whatever()</code> as needed. You need to know that this approach is only safe if the <code>Adult</code> objects always outlive the <code>Child</code> objects. For example, if an order is deleted, all the order items are deleted too, so you don't need to worry about an order item using an invalid pointer to its order. If that's not how things are in your system then you have a bigger problem than pointer syntax to worry about.

blocks|key|1118284|text|这里的问题是my_adult是一个指针，而hand是一个引用。例如，my_adult=&hand可以工作。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1118285|entityMap^0|6|8|L|4|Y|E|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|O|8|@]|D|@]|E|$]]]|G|$]]

The problem here is that <code>my_adult</code> is a pointer, but <code>hand</code> is a reference. <code>my_adult=&amp;hand</code> would work, for example.

blocks|key|2139109|text|您正在尝试将对象赋值给指针。这是行不通的。此外，儿童必须在成人之前定义。否则，必须使用Child作为指针(和转发声明)来定义Adult。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2139110|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You are trying to assign an object to a pointer. It will not work. Also Child must be defined before Adult. Otherwise, Adult must be defined with Child as a pointer (and a forward declaration).

I know <code>this</code> is already a pointer, but I want to understand what <code>this</code> is exactly. Is it an address or is it a * type pointer?

If I were to store this into a variable how would I have to define that variable?

Lets take this as an example

<pre><code>class Adult
{
private:
 Child child;

public:
 Adult(){
 child = new Child(this);
 //to have something to hold onto and get back to the upper level of the hierarchy.
 }
};


class Child
{
private:
 Adult* my_adult;

public:
 Child();
 Child(Adult &amp;hand){
 my_adult = hand;
 }
}
</code></pre>

Okay, so where I run into the trouble is with the line of code that goes <code>my_adult = hand;</code>
It outputs this when I try to build the project, I will be horribly shocked if there are more behind this one.

<pre><code>sys/chin.cpp:19:14: error: cannot convert ‘Adult’ to ‘Adult*’ in assignment
</code></pre>

So how does this work when being dealt with as a data type opposed to accessing members?

Unable to pass this-> pointer to a sub object

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我知道this已经是一个指针，但我想知道this到底是什么。它是一个地址还是一个*类型的指针？如果我将其存储到一个变量中，我将如何定义该变量？让我们以此为例class Adult{private: Child child;public: Adult(){  child = new Child(this);  //to ...

问无法将此->指针传递给子对象
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问无法将此->指针传递给子对象EN