enum class launch{
	async,deferred,sync=deferred,any=async|deferred
};

#include <iostream>
#include <future>
#include <thread>
using namespace std;
int find_result_to_add() {
	//std::this_thread::sleep_for(std::chrono::seconds(2)); // 用來測(cè)試異步延遲的影響
	std::cout << "find_result_to_add" << std::endl;
	return 1 + 1;
}
int find_result_to_add2(int a, int b) {
	//std::this_thread::sleep_for(std::chrono::seconds(5)); // 用來測(cè)試異步延遲的影響
	return a + b;
}
void do_other_things() {
	std::cout << "do_other_things" << std::endl;
	std::this_thread::sleep_for(std::chrono::seconds(5));
}
int main() {
	//async異步 
	std::future<int> result = std::async(std::launch::async,find_result_to_add);
	//std::future<decltype (find_result_to_add())> result = std::async(find_result_to_add);
	//auto result = std::async(find_result_to_add); // 推薦的寫法用aoto 

	do_other_things();

	std::cout << "result: " << result.get() << std::endl; // 延遲是否有影響？

	//std::future<decltype (find_result_to_add2(0, 0))> result2 = std::async(find_result_to_add2, 10, 20);
	//不寫默認(rèn)any 
	auto result2=std::async(find_result_to_add2, 10, 20);

	std::cout << "result2: " << result2.get() << std::endl; // 延遲是否有影響？

	std::cout << "main finish" << endl;
	return 0;
}

#include <iostream>
#include <future>
using namespace std;
int add(int a, int b, int c) {
	std::cout << "call add\n";
	return a + b + c;
}
void do_other_things() {
	std::cout << "do_other_things" << std::endl;
}
int main() {
	std::packaged_task<int(int, int, int)> task(add); // 封裝任務(wù)
	do_other_things();
	std::future<int> result = task.get_future();
	task(1, 1, 2); //必須要讓任務(wù)執(zhí)行，否則在get()獲取future的值時(shí)會(huì)一直阻塞
	std::cout << "result:" << result.get() << std::endl;
	return 0;
}

#include <future>
#include <string>
#include <thread>
#include <iostream>
using namespace std;
void print(std::promise<std::string>& p) {
	p.set_value("There is the result whitch you want.");
}
void do_some_other_things() {
	std::cout << "Hello World" << std::endl;
}
int main() {
	std::promise<std::string> promise;
	std::future<std::string> result = promise.get_future();

	std::thread th(print, std::ref(promise));

	do_some_other_things();
	std::cout << result.get() << std::endl;

	th.join();
	return 0;
}

//保存普通函數(shù)
void func1(int a) {
	cout << a << endl;
}
//1. 保存普通函數(shù)
std::function<void(int a)> func1_;
func1_ = func1;
func1_(2); //2

//2. 保存lambda表達(dá)式
std::function<void()> func2_ = []() {
	cout << "hello lambda" << endl;
};
func2_(); //hello world

//保存成員函數(shù)
class A {
	public:
		A(string name) : name_(name) {}
		void func3(int i) const {
			cout <<name_ << ", " << i << endl;
		}
	private:
		string name_;
};

//3 保存成員函數(shù)
	std::function<void(const A&,int)> func3_ = &A::func3;
	A a("wxf");
	func3_(a, 20);

#include <iostream>
#include <functional>
using namespace std;
//保存普通函數(shù)
void func1(int a) {
	cout << a << endl;
}
//保存成員函數(shù)
class A {
	public:
		A(string name) : name_(name) {}
		void func3(int i) const {
			cout <<name_ << ", " << i << endl;
		}
	private:
		string name_;
};
int main() {
	cout << "main1 -----------------" << endl;
	//1. 保存普通函數(shù)
	std::function<void(int a)> func1_;
	func1_ = func1;
	func1_(2); //2

	cout << "\n\nmain2 -----------------" << endl;
	//2. 保存lambda表達(dá)式
	std::function<void()> func2_ = []() {
		cout << "hello lambda" << endl;
	};
	func2_(); //hello world

	cout << "\n\nmain3 -----------------" << endl;
	//3 保存成員函數(shù)
	std::function<void(const A&,int)> func3_ = &A::func3;
	A a("wxf");
	func3_(a, 20);
	return 0;
}

main1 -----------------
2
main2 -----------------
hello lambda
main3 -----------------
wxf, 20

#include <iostream>
#include <functional>
using namespace std;

void fun_1(int x,int y,int z) {
	cout<<"fun_1 print unchanged: x=" <<x<<",y="<< y << ",z=" <<z<<endl;
}
void fun_2(int &a,int &b) {
	a++;
	b++;
	cout<<"fun_2 print Increment: a=" <<a<<",b="<<b<<endl;
}
class A {
	public:
		// 重載fun_3，主要bind的時(shí)候需要
		// std::bind((void(A::*)(int, int))&A::fun_3
		void fun_3(int k,int m) {
			cout << "fun_3 a = " << a << cout <<"\t print unchanged: k="<<k<<",m="<<m<<endl;
		}
		// std::bind((void(A::*)(string))&A::fun_3
		void fun_3(string str) {
			cout<<"fun_3 print: str="<<str<<endl;
		}
		int a;
};
int main() {
	//f1的類型為 function<void(int, int, int)>
	cout << "\n\nstd::bind(fun_1, 1, 2, 3) -----------------\n";
	auto f1 = std::bind(fun_1, 1, 2, 3); //表示綁定函數(shù) fun 的第一，二，三個(gè)參數(shù)值為：1 2 3
	f1(); //print: x=1,y=2,z=3

	cout << "\n\nstd::bind(fun_1, 10, 20, 30) -----------------\n";
	auto f1_1 = std::bind(fun_1, 10, 20, 30); //表示綁定函數(shù) fun 的第一，二，三個(gè)參數(shù)值為： 1 2 3
	f1_1();

	cout << "\n\nstd::bind(fun_1, placeholders::_1,placeholders::_2, 3) -----------------\n";
	auto f2 = std::bind(fun_1, placeholders::_1, placeholders::_2, 3);
	//表示綁定函數(shù) fun_1的第三個(gè)參數(shù)為 3，而fun_1的第一，二個(gè)參數(shù)分別由調(diào)用 f2 的第一，二個(gè)參數(shù)指定
	f2(1,2);//print: x=1,y=2,z=3
	f2(10,21,30); // 傳入30也沒有用

	cout << "\n\nstd::bind(fun_1,placeholders::_2,placeholders::_1,3) -----------------\n";
	auto f3 = std::bind(fun_1,placeholders::_2,placeholders::_1,3);
	//表示綁定函數(shù) fun_1 的第三個(gè)參數(shù)為 3，而fun_1的第一，二個(gè)參數(shù)分別由調(diào)用 f3 的第二，一個(gè)參數(shù)指定
	//注意： f2 和 f3 的區(qū)別。
	f3(1,2);//print: x=2,y=1,z=3

	cout << "\n\nstd::bind(fun_2, placeholders::_1, n) -----------------\n";
	int m = 2;
	int n = 3;
	////表示綁定fun_2的第一個(gè)參數(shù)為n, fun_2的第二個(gè)參數(shù)由調(diào)用f4的第一個(gè)參數(shù)（_1）指定。
	auto f4 = std::bind(fun_2, placeholders::_1, n); //func_2(3,<f4_1>)
	f4(m); //print: m=3,n=4
	cout<<"m="<<m<<endl;//m=3 說明：bind對(duì)于不事先綁定的參數(shù)，通過std::placeholders傳遞的參數(shù)是通過引用傳遞的,如m
	cout<<"n="<<n<<endl;//n=3 說明：bind對(duì)于預(yù)先綁定的函數(shù)參數(shù)是通過值傳遞的，如n

	cout << "\n\nstd::bind(&A::fun_3,&a1,40,50) -----------------\n";
	A a;
	a.a = 10;
	//f5的類型為 function<void(int, int)>
	auto f5 = std::bind((void(A::*)(int, int))A::fun_3, &a, 40, 50); 
	f5(10,20);//參數(shù)以及寫死，傳參沒用 

	cout << "\n\nstd::bind(&A::fun_3, &a2,placeholders::_1,placeholders::_2) -----------------\n";
	A a2;
	a2.a = 20;
	//f5的類型為 function<void(int, int)>
	auto f6 = std::bind((void(A::*)(int, int))&A::fun_3,&a2,placeholders::_1,placeholders::_2); //使用auto關(guān)鍵字
	f6(10,20);//調(diào)用a.fun_3(10,20),print: k=10,m=20

	cout << "\n\nstd::bind(&A::fun_3,a3,std::placeholders::_1,std::placeholders::_2) -----------------\n";
	std::function<void(int,int)> fc = std::bind((void(A::*)(int,int))&A::fun_3, &a,std::placeholders::_1,std::placeholders::_2);
	fc(10,20); //調(diào)用a.fun_3(10,20) print: k=10,m=20
	fc = std::bind((void(A::*)(int, int))&A::fun_3,&a2,std::placeholders::_1,std::placeholders::_2);

	cout << "\n\nstd::bind(&A::fun_3,&a1,std::placeholders::_1) -----------------\n";
	auto f_str = std::bind((void(A::*)(string))&A::fun_3,a,std::placeholders::_1);
	f_str("wxf");

	return 0;
}