#include<iostream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<algorithm>
#include<functional>
using namespace std;

template<typename T>
class ShowElemt
{
public:
	ShowElemt()
	{
		n = 0;
	}
	void operator()(T&t)
	{
		n++;
//		printN();
		cout << t <<" ";
	}
	void printN()
	{
		cout << "n:" << n << " ";
	}
private:
	int n;

};

//模板函式
template<typename T>
void FunShowElemt(T  &t)
{
	cout << "FunShowElemt:" << t << " ";
}

//普通函式
void FunShowElemt2(int  &t)
{

	cout << "FunShowElemt2:" << t << " ";
}

void main01()
{
	int a = 10;
	ShowElemt<int> showElemt;
	showElemt(a);//函式物件的執行很像一個函式 偽函式

	FunShowElemt<int>(a);
	FunShowElemt2(a);
}

//函式物件是屬於類物件，能突破函式概念，能保持呼叫狀態資訊
//for_each演算法中 函式物件做函式引數
//for_each演算法中 函式物件當返回值

void main02()
{
	vector<int> v1;
	v1.push_back(1);
	v1.push_back(3);
	v1.push_back(5);

	for_each(v1.begin(), v1.end(), ShowElemt<int>());
	cout << endl;
	for_each(v1.begin(), v1.end(), FunShowElemt2);
	cout << endl;

	ShowElemt<int> show1;

	/*
	template<class _InIt,class _Fn1> inline	_Fn1 for_each(_InIt _First, _InIt _Last, _Fn1 _Func)
	{	// perform function for each element
		_DEBUG_RANGE(_First, _Last);
		_DEBUG_POINTER(_Func);
		_For_each(_Unchecked(_First), _Unchecked(_Last), _Func);

	return (_STD move(_Func));
	}
	*/
	

	//for_each演算法的函式 物件的傳遞 是元素值傳遞，不是引用傳遞
	for_each(v1.begin(), v1.end(), show1);
	show1.printN();

	cout << endl;

	show1 = for_each(v1.begin(), v1.end(), show1);//通過for_each演算法的返回值看呼叫的次數
	show1.printN();
//結論要點：分清楚 stl演算法返回的值是迭代器還是謂詞（函式物件）是stl演算法入門的重要點
}