[英]Why does my istream_iterator not work?
这是我编写的代码。 我正在使用Visual Studio,并学习如何使用标准模板库。 当我尝试从来源打印时, ostream_iterator
也不起作用。 它给出了大量错误,我可能无法理解。
这是我试图在Visual Studio中运行的完整代码。 软件设置可能有问题吗?
#include <iostream>
#include <vector>
#include <list>
#include <iterator>
#include <functional>
using namespace std;
//stream_iterator
int main() {
vector<string> source = { "31", "3113" };
copy(istream_iterator<string>(cin), istream_iterator<string>(),back_inserter(source)); //can't understand why this won't work
return 0;
}
These below are the error messages.
1>------ Build started: Project: StreamIters, Configuration: Debug Win32 ------
1> Source.cpp
1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\iterator(256): error C2679: binary '>>' : no operator found which takes a right-hand operand of type 'std::string' (or there is no acceptable conversion)
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(485): could be 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(std::basic_streambuf<char,std::char_traits<char>> *)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(466): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(void *&)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(448): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(long double &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(430): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(double &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(411): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(float &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(392): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(unsigned __int64 &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(373): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(__int64 &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(353): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(unsigned long &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(335): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(long &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(317): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(unsigned int &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(291): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(int &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(272): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(unsigned short &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(237): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(short &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(218): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(std::_Bool &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(211): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(std::ios_base &(__cdecl *)(std::ios_base &))'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(204): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(std::basic_ios<char,std::char_traits<char>> &(__cdecl *)(std::basic_ios<char,std::char_traits<char>> &))'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(198): or 'std::basic_istream<char,std::char_traits<char>> &std::basic_istream<char,std::char_traits<char>>::operator >>(std::basic_istream<char,std::char_traits<char>> &(__cdecl *)(std::basic_istream<char,std::char_traits<char>> &))'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(1103): or 'std::basic_istream<char,std::char_traits<char>> &std::operator >><char,std::char_traits<char>,_Ty>(std::basic_istream<char,std::char_traits<char>> &&,_Ty &)'
1> with
1> [
1> _Ty=std::string
1> ]
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(1093): or 'std::basic_istream<char,std::char_traits<char>> &std::operator >><std::char_traits<char>>(std::basic_istream<char,std::char_traits<char>> &,unsigned char &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(1086): or 'std::basic_istream<char,std::char_traits<char>> &std::operator >><std::char_traits<char>>(std::basic_istream<char,std::char_traits<char>> &,unsigned char *)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(1079): or 'std::basic_istream<char,std::char_traits<char>> &std::operator >><std::char_traits<char>>(std::basic_istream<char,std::char_traits<char>> &,signed char &)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\istream(1072): or 'std::basic_istream<char,std::char_traits<char>> &std::operator >><std::char_traits<char>>(std::basic_istream<char,std::char_traits<char>> &,signed char *)'
1> while trying to match the argument list '(std::basic_istream<char,std::char_traits<char>>, std::string)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\iterator(255) : while compiling class template member function 'void std::istream_iterator<std::string,char,std::char_traits<char>,ptrdiff_t>::_Getval(void)'
1> c:\program files (x86)\microsoft visual studio 12.0\vc\include\iterator(222) : see reference to function template instantiation 'void std::istream_iterator<std::string,char,std::char_traits<char>,ptrdiff_t>::_Getval(void)' being compiled
1> c:\users\mahe\documents\visual studio 2013\projects\streamiters\streamiters\source.cpp(19) : see reference to class template instantiation 'std::istream_iterator<std::string,char,std::char_traits<char>,ptrdiff_t>' being compiled
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
该代码缺少标题<string>
。 尽管所使用的接口确实要求至少有一个std::string
声明可用,但并不要求您包含的标头提供std::string
和/或在其上运行的函数的定义。 我没有安装MSVC ++,但似乎您包含的标头提供了std::string
的定义,但没有输入或输出运算符的声明。
根据经验,您永远不应依赖间接包含。 相反,您应该始终明确地包括所有相关的标头:尽管声明当前可能可用,但标头可能会更改为不包含其他标头。
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