c++怎么使用std::invoke统一调用各种可调用对象_c++ invoke实现通用调用方式

std::invoke(callable, args...);

#include <iostream>
#include <functional>

struct Person {
    std::string name;
    void greet() const { std::cout << "Hello, I'm " << name << "\n"; }
    int getAge() const { return 25; }
};

void say_hello() {
    std::cout << "Hello from function!\n";
}

int main() {
    // 调用普通函数
    std::invoke(say_hello);

    // 调用 lambda
    auto lambda = []() { std::cout << "Hello from lambda!\n"; };
    std::invoke(lambda);
}

Person p{"Alice"};

// 调用成员函数：需要传入成员函数指针和对象（或指针）
std::invoke(&Person::greet, p);        // 使用对象
std::invoke(&Person::greet, &p);       // 使用指针

int age = std::invoke(&Person::getAge, p);
std::cout << "Age: " << age << "\n";

struct Printer {
    void operator()(const std::string& msg) const {
        std::cout << "[Log] " << msg << "\n";
    }
};

Printer printer;
std::invoke(printer, "test message");
// 或者直接传 lambda
std::invoke([](int x) { std::cout << "x = " << x << "\n"; }, 42);

template <typename Callable, typename... Args>
auto call_any(Callable&& c, Args&&... args) 
    -> decltype(std::invoke(std::forward<Callable>(c), std::forward<Args>(args)...)) {
    return std::invoke(std::forward<Callable>(c), std::forward<Args>(args)...);
}

call_any(say_hello);
call_any(&Person::greet, p);
call_any([]{ std::cout << "Lambda called\n"; });