c++ - std::count 错误

Question

  temp_holder.clear();
  temp_holder << n;
  n_str = temp_holder.str();
  int f = count(n_str.begin(), n_str.end(), a);

这是我的代码，这是 g++ 输出:

In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h: In instantiation of ‘typename std::iterator_traits<_InputIterator>::difference_type std::count(_IIter, _IIter, const _Tp&) [with _IIter = __gnu_cxx::__normal_iterator<char*, std::basic_string<char> >; _Tp = std::basic_string<char>; typename std::iterator_traits<_InputIterator>::difference_type = long int]’:
trintatres.cpp:44:50:   required from here
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: error: no match for ‘operator==’ in ‘__first.__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator*<char*, std::basic_string<char> >() == __value’
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note: candidates are:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iosfwd:42:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:39,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/postypes.h:218:5: note: template<class _StateT> bool std::operator==(const std::fpos<_StateT>&, const std::fpos<_StateT>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/postypes.h:218:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::fpos<_StateT>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algobase.h:65:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/char_traits.h:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_pair.h:212:5: note: template<class _T1, class _T2> bool std::operator==(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_pair.h:212:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::pair<_T1, _T2>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algobase.h:68:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/char_traits.h:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:293:5: note: template<class _Iterator> bool std::operator==(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:293:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::reverse_iterator<_Iterator>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algobase.h:68:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/char_traits.h:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:343:5: note: template<class _IteratorL, class _IteratorR> bool std::operator==(const std::reverse_iterator<_IteratorL>&, const std::reverse_iterator<_IteratorR>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:343:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::reverse_iterator<_IteratorL>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/string:43:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_classes.h:42,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/ios_base.h:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/allocator.h:119:5: note: template<class _T1, class _T2> bool std::operator==(const std::allocator<_T1>&, const std::allocator<_T2>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/allocator.h:119:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::allocator<_T1>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/string:43:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_classes.h:42,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/ios_base.h:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/allocator.h:124:5: note: template<class _Tp> bool std::operator==(const std::allocator<_Tp1>&, const std::allocator<_Tp1>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/allocator.h:124:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::allocator<_Tp1>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/string:54:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_classes.h:42,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/ios_base.h:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2483:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const std::basic_string<_CharT, _Traits, _Alloc>&, const std::basic_string<_CharT, _Traits, _Alloc>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2483:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::basic_string<_CharT, _Traits, _Alloc>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/string:54:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_classes.h:42,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/ios_base.h:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2490:5: note: template<class _CharT> typename __gnu_cxx::__enable_if<std::__is_char<_Tp>::__value, bool>::__type std::operator==(const std::basic_string<_CharT>&, const std::basic_string<_CharT>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2490:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::basic_string<_CharT>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/string:54:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_classes.h:42,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/ios_base.h:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2504:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const _CharT*, const std::basic_string<_CharT, _Traits, _Alloc>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2504:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const _CharT*’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/string:54:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_classes.h:42,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/ios_base.h:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2516:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const std::basic_string<_CharT, _Traits, _Alloc>&, const _CharT*)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_string.h:2516:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::basic_string<_CharT, _Traits, _Alloc>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_facets.h:50:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/basic_ios.h:39,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:45,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/streambuf_iterator.h:206:5: note: template<class _CharT, class _Traits> bool std::operator==(const std::istreambuf_iterator<_CharT, _Traits>&, const std::istreambuf_iterator<_CharT, _Traits>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/streambuf_iterator.h:206:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const std::istreambuf_iterator<_CharT, _Traits>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/x86_64-unknown-linux-gnu/bits/c++allocator.h:34:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/allocator.h:48,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/string:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/locale_classes.h:42,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/ios_base.h:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:43,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ext/new_allocator.h:129:5: note: template<class _Tp> bool __gnu_cxx::operator==(const __gnu_cxx::new_allocator<_Tp>&, const __gnu_cxx::new_allocator<_Tp>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ext/new_allocator.h:129:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const __gnu_cxx::new_allocator<_Tp>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algobase.h:68:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/char_traits.h:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:813:5: note: template<class _Iterator, class _Container> bool __gnu_cxx::operator==(const __gnu_cxx::__normal_iterator<_Iterator, _Container>&, const __gnu_cxx::__normal_iterator<_Iterator, _Container>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:813:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const __gnu_cxx::__normal_iterator<_Iterator, _Container>’ and ‘char’
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algobase.h:68:0,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/char_traits.h:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ios:41,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/ostream:40,
                 from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/iostream:40,
                 from trintatres.cpp:1:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:807:5: note: template<class _IteratorL, class _IteratorR, class _Container> bool __gnu_cxx::operator==(const __gnu_cxx::__normal_iterator<_IteratorL, _Container>&, const __gnu_cxx::__normal_iterator<_IteratorR, _Container>&)
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_iterator.h:807:5: note:   template argument deduction/substitution failed:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/algorithm:63:0,
                 from trintatres.cpp:5:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_algo.h:4656:2: note:   mismatched types ‘const __gnu_cxx::__normal_iterator<_IteratorL, _Container>’ and ‘char’

老实说，根据 cplusplus.com，我认为我正确地使用了 std::count。

知道我做错了什么吗？

编辑完整代码:

#include <iostream>
#include <string>
#include <sstream>
#include <climits>
#include <algorithm>

using namespace std;

int max(int a, int b) {
  return (a > b) ? a : b;
}

int main() {
  string a;
  cin >> a;

  int c;
  cin >> c;

  int q;
  cin >> q;

  string cases[q];
  int max_case = INT_MIN;
  int temp;
  for (int i = 0; i < q; i++) {
    cin >> temp;
    max_case = max(temp, max_case);
    stringstream current_case_holder;
    current_case_holder << temp;
    cases[i] = current_case_holder.str();
  }

  int sequence[max_case];
  int n;
  stringstream temp_holder;
  string n_str;
  for (int i = 0; i < max_case; i++) {
    n = 1;
    while (true) {
      temp_holder.clear();
      temp_holder << n;
      n_str = temp_holder.str();
      int f = count(n_str.begin(), n_str.end(), a);

      //}

      n++;
    }
  }

  return 0;
}

Answer 1

第一个错误告诉你所有你需要知道的:

In instantiation of ‘typename std::iterator_traits<_InputIterator>::difference_type std::count(_IIter, _IIter, const _Tp&)
[with _IIter = __gnu_cxx::__normal_iterator<char*, std::basic_string<char> >;
        _Tp = std::basic_string<char>;
        typename std::iterator_traits<_InputIterator>::difference_type = long int]’

这表示您传递的是 std::string std::count 的第三个参数的对象，这是错误的；你需要传递 char对象，因为你有效地迭代了 std::string , 和 std::string::value_type是char .