foo.cpp:1:1: error: expected unqualified-id before '?' token
 ??  ???????? ??? ???????i?????????i?????????  ?????? 
 ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:40:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ostream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iostream:39,
                 from foo.cpp:18:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:104:66: error: 'std::size_t' has not been declared
       compare(const char_type* __s1, const char_type* __s2, std::size_t __n);
                                                                  ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:106:14: error: 'size_t' in namespace 'std' does not name a type
       static std::size_t
              ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:110:39: error: 'std::size_t' has not been declared
       find(const char_type* __s, std::size_t __n, const char_type& __a);
                                       ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:113:57: error: 'std::size_t' has not been declared
       move(char_type* __s1, const char_type* __s2, std::size_t __n);
                                                         ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:116:57: error: 'std::size_t' has not been declared
       copy(char_type* __s1, const char_type* __s2, std::size_t __n);
                                                         ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:119:35: error: 'std::size_t' has not been declared
       assign(char_type* __s, std::size_t __n, char_type __a);
                                   ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:145:64: error: 'std::size_t' has not been declared
     compare(const char_type* __s1, const char_type* __s2, std::size_t __n)
                                                                ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h: In static member function 'static int __gnu_cxx::char_traits<_CharT>::compare(const char_type*, const char_type*, int)':
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:147:12: error: 'size_t' is not a member of 'std'
       for (std::size_t __i = 0; __i < __n; ++__i)
            ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:147:12: note: suggested alternative:
In file included from c:\mingw\include\wchar.h:26:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\cwchar:44,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\postypes.h:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iosfwd:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ostream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iostream:39,
                 from foo.cpp:18:
c:\mingw\lib\gcc\mingw32\4.8.1\include\stddef.h:212:23: note:   'size_t'
 typedef __SIZE_TYPE__ size_t;
                       ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:40:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ostream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iostream:39,
                 from foo.cpp:18:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:147:24: error: expected ';' before '__i'
       for (std::size_t __i = 0; __i < __n; ++__i)
                        ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:147:33: error: '__i' was not declared in this scope
       for (std::size_t __i = 0; __i < __n; ++__i)
                                 ^
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h: At global scope:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:156:5: error: 'size_t' in namespace 'std' does not name a type
     std::size_t
     ^
c:\mingw\lib\gcc\mingw32\4.8.1\inc