NULL和null之间的区别 [英] Difference between NULL and null

问题描述

C＃中C ++的NULL等价是什么？



我尝试过：



Null有一个默认值0.它可以用作bool，integer，pointer。但是当我们没有指向某个对象时，会使用C＃null。我不确定在C＃中是否可以使用null代替NULL。

解决方案

没有可以完全以相同方式使用的等价物。你分配的内容取决于你想如何使用它：



o是一个值为0的int：

对象o = 0; 

o是一个值为false的bool：

 object o = false; 

o是一个未分配的对象：

 object o = null; 

< C ++中的blockquote> NULL 只是一个产生零指针的宏（内存地址为零，实际上没有该变量的地址）。

您的问题的答案并不简单：在C＃中使用 null 表示没有对任何对象的引用（对于托管代码）;如果你试图操纵来自C＃的指针（除非你真的知道你在做什么，我实际上不推荐），你可以使用 IntPtr.Zero 代替。

Quote：

Null有一个默认值0

粗略地看一下NULL - cppreference.com [ ^ ]。





C ++ 和 C＃是相当不同的编程语言。因此，您可能会将苹果与橙子进行比较。

what is the equivalent of NULL of C++ in C#?

What I have tried:

Null has a default value 0. it can be used as bool,integer, pointer. But C# null is used when we are not pointing to some object. I am not sure whether null can be used in place of NULL in C#.

解决方案

There's no equivalent that can be used in exactly the same way. What you assign depends on how you want to use it:

o is an int with value 0:

object o = 0;

o is a bool with value false:

object o = false;

o is an unassigned object:

object o = null;

NULL in C++ is just a macro which yields to a zero-pointer (a memory address of zero, meaning no address for that variable really).
The answer to your question is not straightforward: use null in C# to denote the absence of a reference to any object (for managed code); if you are trying to manipulate pointers from C# (which I actually do not recommend unless you really know what you are doing), you could use IntPtr.Zero instead.

Quote:

Null has a default value 0

Roughly, see NULL - cppreference.com[^].


C++ and C# are rather different programming languages. So you risk to compare apple with oranges.

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