如何使用SFINAE为容器创建模板函数，并根据运算符推断返回类型？

#include <iostream>
#include <type_traits>
#include <vector>
#include <list>

// 定义一个模板函数，使用SFINAE进行重载和返回类型推断
template<typename Container>
typename std::enable_if<std::is_same<typename Container::value_type, int>::value, int>::type
sum(const Container& container) {
    int result = 0;
    for (const auto& element : container) {
        result += element;
    }
    return result;
}

template<typename Container>
typename std::enable_if<std::is_same<typename Container::value_type, std::string>::value, std::string>::type
concatenate(const Container& container) {
    std::string result;
    for (const auto& element : container) {
        result += element;
    }
    return result;
}

int main() {
    std::vector<int> numbers = {1, 2, 3, 4, 5};
    std::list<std::string> strings = {"Hello", ", ", "world", "!"};

    int sumResult = sum(numbers);
    std::string concatResult = concatenate(strings);

    std::cout << "Sum result: " << sumResult << std::endl;
    std::cout << "Concatenate result: " << concatResult << std::endl;

    return 0;
}