c++tricks——模板函数重载

vs2015 c++编译器规则：

• A template specialization for a specific type is more specialized than one taking a generic type argument.
• A template taking only T* is more specialized than one taking only T, because a hypothetical type X* is a valid argument for a T template argument, but X is not a valid argument for a T* template argument.（T*与T区别）
• const T is more specialized than T, because const X is a valid argument for a T template argument, but X is not a valid argument for a const T template argument.（const T与T区别）
• const T* is more specialized than T*, because const X* is a valid argument for a T* template argument, but X* is not a valid argument for a const T* template argument.（const T*与T*区别）

// partial_ordering_of_function_templates.cpp   // compile with: /EHsc   #include <iostream>      extern "C" int printf(const char*,...);   template <class T> void f(T) {      printf_s("Less specialized function called\n");   }   template <class T> void f(T*) {      printf_s("More specialized function called\n");   }   template <class T> void f(const T*) {      printf_s("Even more specialized function for const T*\n");   }      int main() {      int i =0;      const int j = 0;      int *pi = &i;      const int *cpi = &j;         f(i);   // Calls less specialized function.      f(pi);  // Calls more specialized function.      f(cpi); // Calls even more specialized function.      // Without partial ordering, these calls would be ambiguous.   }   /** output Less specialized function called   More specialized function called   Even more specialized function for const T*   */