xcode - Xcode7: unknown type name error in a basic C++ program -

i working on c++ program stl latest version of xcode, , error "unknown type name 'ubresultdata'" , "unknown type name 'ubfirstargument'". have tried rewrite program standard unary_function , binary_function, , errors remained same. then, build progaram vs2010 , vs2013, , built successfully. what's wrong program?

the errors in last line of class binder2nd.

#include <iostream> #include <vector> using namespace std;  template<typename inputiterator, typename predicator> inline int countif(inputiterator first, inputiterator last, predicator pred){     int count = 0;     (; first != last; ++first) {         if(pred(*first))++count;     }      return count; }  template<typename arg1, typename result> struct unarybase{     typedef arg1 ubfirstargument;     typedef result ubresultdata; };  template<typename arg1, typename arg2, typename result> struct binarybase{     typedef arg1 bbfirstargument;     typedef arg2 bbsecondargument;     typedef result bbresultdata; };  template<typename t> struct less:public binarybase<t, t, bool>{     bool operator()(const t& left, const t& right)const{         return (left < right);     } };  template<typename binop> class binder2nd:public unarybase<typename binop::bbfirstargument, typename binop::bbresultdata>{ protected:     binop op;     typename binop::bbsecondargument arg2; public:     binder2nd(const binop& oper, const typename binop::bbsecondargument& valright):op(oper),arg2(valright){}     ubresultdata operator()(const ubfirstargument &ubarg1)const{return op(ubarg1,arg2);} };  template<typename binop, typename rightval> binder2nd<binop> bind2nd(const binop& op, const rightval& vright){     return binder2nd<binop>(op, vright); }  int main(){     vector<int> myvec;     (int = 0; < 50; ++i) {         myvec.push_back(rand()%100);     }      int countnum = countif(myvec.begin(), myvec.end(), bind2nd(less<int>(), 30));     cout << "numbers=" << countnum << endl;      return 0; } 

i don't remember exact phrasing standard, here's simplified code demonstrates same behavior yours:

template <typename t> struct {   typedef t x; };  template <typename t> struct b: public a<t> {   x x(void) { return 5; } }; 

and here's version compiles without errors:

template <typename t> struct {   typedef t x; };  template <typename t> struct b: public a<t> {   typename a<t>::x x(void) { return 5; } }; 

so basically, need specify type comes from.

it looks vs* compilers bit more permissive gcc or clang. :)