VC.STL Newsgroup Good Questions(二)

VC.STL Newsgroup Good Questions(二)

    使用Templated Member Function时C2664编译错误，Why?

Article last modified on 2002-5-29

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The information in this article applies to:

-        Microsoft Visual C++, 32-bit Editions, version 6.0, SP5

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Question:

下面的代码编译时报告C2664错误：

Error C2664: '__thiscall std::list<int,class std::allocator<int> >::std::list<int,class std::allocator<int> >(unsigned int,const int &,const class std::allocator<int> &)' : cannot convert parameter 1 from 'class std::istream_iterator<int,char,struct std::char_traits<char> > (__cdecl *)(void)' to 'unsigned int'        This conversion requires a reinterpret_cast, a C-style cast or function-style cast

代码如下：
istream_iterator<int> intFileBegin();

istream_iterator<int> intFileEnd;

list<int> intList(intFileBegin, intFileEnd);

 

Answer:

当VC6的库文件刚发布的时候，编译器还不支持Templated Member Function。这样，Templated List Constructor无法得到Non-List Iterators。

现在编译器虽然支持Templated Member Function，但要想编译通过，你还是需要一个新的标准库。前面的代码应该在以下环境中可以编译通过：

n        VC 7

n        VC6 with Dinkumware library upgrade

n        VC6 with STLport

 

如果你没有这样的编译环境，那还是不要使用Templated Member Function。你可以这么做：

istream_iterator<int> intFileBegin(cin);

istream_iterator<int> intFileEnd;

list<int> intList;

copy(intFileBegin,intFileEnd,back_inserter(intList));

 

这样同样可以把istream中的东西导入到list中。

 

(To be Continued)

 

Written by zhengyun@tomosoft.com

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