36. function实现原理

Posted 2022-12-05 干锅土鸡

void hello(string str)

	cout << str << endl;

int sum(int a,int b)

	return a+b;



template<typename FTy>
class myfunction
;

template<typename R,typename A1>
class myfunction<R(A1)>

public:
	using PFUNC = R(*)(A1);
	myfunction(PFUNC pfunc):_pfunc(pfunc)
	
	R operator()(A1 arg)
	
		return _pfunc(arg);
	
private:
	PFUNC _pfunc;
;

template<typename R,typename A1,typename A2>
class myfunction<R(A1,A2)>

public:
	using PFUNC = R(*)(A1,A2);
	myfunction(PFUNC pfunc):_pfunc(pfunc)
	
	R operator()(A1 arg1,A2 arg2)
	
		return _pfunc(arg1,arg2);
	
private:
	PFUNC _pfunc;
;

//以下为最终版本：
template<typename R,typename...A>
class myfunction<R(A...)>

public:
	using PFUNC = R(*)(A...);
	myfunction(PFUNC pfunc):_pfunc(pfunc)
	R operator()(A... arg)
	
		return _pfunc(arg...);
	
private:
	PFUNC _pfunc;
;
int main()

	myfunction<void(string)> func1(hello);
	func1("hello world！");//func1.operator()("hello world!")

	myfuncion<int(int,int)> func2(sum);
	cout << func2(10,20) << endl;