c++ - 如何正确重载函数

Question

您好，我只是想知道如何在二叉搜索树中正确地重载函数。这是我的代码:

int LessThan(E itm1, E itm2) {
  if (itm1 < itm2) {return -1;}
  else if (itm1 > itm2) {return 1;}
  else if (itm1 == itm2) {return 0;}
}

int LessThan(string s1, string s2) { // Incase it is a string, we need to define <= and >= differently
  return this->compare(s1, s2);
}

不幸的是，我收到以下错误:

binarySearchTree.h:33:9: error: ‘int binarySearchTree<E>::LessThan(std::__cxx11::string, std::__cxx11::string) [with E = std::__cxx11::basic_string<char>; std::__cxx11::string = std::__cxx11::basic_string<char>]’ cannot be overloaded
 int LessThan(string s1, string s2) { // Incase it is a string, we need to define <= and >= differently
     ^
binarySearchTree.h:27:9: error: with ‘int binarySearchTree<E>::LessThan(E, E) [with E = std::__cxx11::basic_string<char>]’
 int LessThan(E itm1, E itm2) {
     ^

Answer 1

重载不是您问题的答案。当您的模板使用 std::string 实例化时，您正在尝试具有特定行为。正确的技术是显式特化。在您的模板定义下添加以下内容，如下所示:

template<>
int binarySearchTree<std::string>::LessThan(std::string s1, std::string s2) {
  return this->compare(s1, s2);
}