vector find和find_if用法

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

class Stock
{
public:
	Stock(long n, double a, double b);
	Stock() {};
	void Show();
	long GetShares();
	long shares;
	double share_val;
	double total_val;
	bool operator == (const int& i) const
	{
		return this->shares == i;
	}

	bool cmp() 
	{
		return this->shares == 4;
	}


};

class findx {
public:
	findx(const int i){ num = i; }
	bool operator()(Stock& dValue) {
		if (dValue.shares == num)
			return true;
		else
			return false;
	}

private:
	int num;

};

Stock::Stock(long n, double a, double b)
{
	shares = n;
	share_val = a;
	total_val = b;
}

long Stock::GetShares()
{
	return shares;
}

void Stock::Show()
{
	cout << "shares = " << shares << endl;
	cout << "share_val = " << share_val << endl;
	cout << "total_val = " << total_val << endl;
}

bool cmp(Stock stock)
{
	return stock.shares == 4;
}

bool cmp2(int a)
{
	return a == 5;
}

bool CompareShares(Stock &stock1, int num)
{
	return stock1.shares == num;
}

struct compare : binary_function<Stock, int, bool> {

	bool operator()(Stock &value, int num) const

	{

		if (value.shares == num)
			return true;
		else
			return false;
	}

};


int main()
{
	Stock stock1(1, 2, 3);
	//stock1.Show();
	Stock stock2(4, 5, 6);
	Stock stock3(7, 8, 9);
	vector<Stock> s(10);
	s.push_back(stock1);
	s.push_back(stock2);
	s.push_back(stock3);
	int size = s.size();
	for (int i = 0; i < size; i++)
	{
		if (s[i].shares == 4)
		{
			s[i].shares = 5;
			cout << "find it" << endl;
		}
	}
	//cout << stock2.shares << endl;
	s[1].shares = 5;
	cout << stock2.shares << endl;
	vector<Stock>::iterator iter = find_if(s.begin(), s.end(), findx(4));
	//vector<Stock>::iterator iter = find_if(s.begin(), s.end(), cmp);
	//vector<Stock>::iterator iter = find_if(s.begin(), s.end(), bind2nd(compare(), 4));
	//vector<Stock>::iterator iter = find_if(s.begin(), s.end(), [](Stock &value) {return value == 4; });
	//vector<Stock>::iterator iter = find_if(s.begin(), s.end(), bind2nd(ptr_fun(CompareShares), 4));
	if (iter != s.end())
	{
		iter->shares = 5;
		cout << iter->shares << endl;
	}
	else
		cout << "not find it" << endl;
	cout << stock2.shares << endl;
	cout << s[1].shares << endl;

	system("pause");
	return 0;
}

 

 

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<functional>
using namespace std;
class Item
{
private:
	std::string  m_ItemId;
	int m_Price;
	int m_Count;
public:
	Item(std::string id, int price, int count) :
		m_ItemId(id), m_Count(count), m_Price(price) {}
	int getCount() const {
		return m_Count;
	}
	std::string getItemId() const {
		return m_ItemId;
	}
	int getPrice() const {
		return m_Price;
	}
	bool operator==(const Item & obj2) const
	{
		if (this->getItemId().compare(obj2.getItemId()) == 0)
			return true;
		else
			return false;
	}

	bool Compare(int num)
	{
		if (this->getPrice() == num)
			return true;
		else
			return false;
	}
};

bool priceComparision(Item & obj, int y)
{
	if (obj.getPrice() == y)
		return true;
	else
		return false;
}

std::vector<Item> getItemList()
{
	std::vector<Item> vecOfItems;
	vecOfItems.push_back(Item("D121", 100, 2));
	vecOfItems.push_back(Item("D122", 12, 5));
	vecOfItems.push_back(Item("D123", 28, 6));
	vecOfItems.push_back(Item("D124", 8, 10));
	vecOfItems.push_back(Item("D125", 99, 3));
	return vecOfItems;
}

int main()
{
	std::vector<Item> vecOfItems = getItemList();
	std::vector<Item>::iterator it;
	//it = std::find_if(vecOfItems.begin(), vecOfItems.end(), std::bind(priceComparision, std::placeholders::_1, 28));
	it = std::find_if(vecOfItems.begin(), vecOfItems.end(), std::bind(&Item::Compare, std::placeholders::_1, 28));
	if (it != vecOfItems.end())
		std::cout << "Item Price ::" << it->getPrice() << " Count :: " << it->getCount() << std::endl;
	else
		std::cout << "Item not Found" << std::endl;
	return 0;
}