c++ - How is a method taking const char* as argument a near match to a method taking const int&? -

the following code throws compiler error when compile it.

template <typename t> inline t const& max (t const& a, t const& b) {     return < b ? b : a; }  // maximum of 2 c-strings (call-by-value) inline char const* max (char const* a, char const* b) {     return strcmp(a,b) < 0 ? b : a; }  // maximum of 3 values of type (call-by-reference) template <typename t> inline t const& max (t const& a, t const& b, t const& c) {     return max (max(a,b), c);  }  int main () {     ::max(7, 42, 68);   } 

on compilation error :

error: call of overloaded 'max(const int&, const int&)' ambiguous

note: candidates are:

note: const t& max(const t&, const t&) [with t =int]

note: const char* max(const char*, const char*)

how max(const char*, const char*) becomes near match max(const int&, const int &) when have template method matches call?

i bet have using namespace std in code. remove , you'll fine.

compare: http://ideone.com/csq8sv , http://ideone.com/iqaoi6

if strictly need namespace std used, can force root namespace call (the way in main()):

template <typename t> inline t const& max (t const& a, t const& b, t const& c) {     return ::max(::max(a,b), c);  }