什么头文件在 C++ 中定义了 NULL?
根据C++ 入门，<cstdlib> 头定义了 NULL.cpluspplus 说它是在
According to C++ primer, <cstdlib> header defines NULL. cpluspplus says it is defined in <cstddef>.
最终，如果不包含正确的标题，我认为无法引用 NULL.
Ultimately, if the right header is not included, I thought NULL can't be referenced.
据我所知，在仅包含 <iostream>
请帮助我理解这一点.
推荐答案
C++03 section 18.1.2 说在 cstddef 中定义了 NULL.
C++03 section 18.1.2 says that NULL is defined in cstddef.
在某些实现中，iostream 可能包含 cstddef，因此包含 iostream 也会为您提供 NULL.
On some implementations, iostream may include cstddef, so including iostream would also give you NULL.
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