STL的find，find_if函数提供了一种对数组、STL容器进行查找的方法。使用该函数，需添加
 #include <algorithm>

我们查找一个vector中的数据，通常用std::find()，例如：

#include <vector>
#include <algorithm>

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
	std::vector<std::string> vec;
	vec.push_back("one");
	vec.push_back("two");
	vec.push_back("three");
	//查找
	std::vector<std::string>::iterator it = std::find(vec.begin(), vec.end(), "two");
	if (it != vec.end())
		printf("find:%s\n", it->c_str());
	else
		printf("not found.\n");
}

运行结果：

 

#include <vector>
#include <algorithm>
#include <string>

using namespace std;

typedef struct _ProductAccount
{
	std::string Product;
	std::string Account;

} ProductAccount;

typedef std::vector<ProductAccount> ProductAccountVec;

typedef struct finder_t
{
	finder_t(std::string p):product(p)
	{
	}

	bool operator()(ProductAccount p)
	{
		return	(product.compare(p.Product) == 0);
	}

	std::string product;

} finder_t;

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
	ProductAccountVec vecProductAccount;

	ProductAccount pa1 = {"p1", "a1"};
	vecProductAccount.push_back(pa1);

	ProductAccount pa2 = {"p2", "a1"};
	vecProductAccount.push_back(pa2);

	ProductAccount pa3 = {"p2", "a2"};
	vecProductAccount.push_back(pa3);

	ProductAccount pa4 = {"p1", "a3"};
	vecProductAccount.push_back(pa4);

	//通过产品查找账号（多对多的关系，所以有多个结果）
	std::vector<string> vecAccount;
	ProductAccountVec::iterator it = vecProductAccount.begin();
	while((it = std::find_if(it, vecProductAccount.end(), finder_t("p1"))) != vecProductAccount.end())
	{
		vecAccount.push_back(it++->Account);
	}

	for(std::vector<string>::iterator it = vecAccount.begin(); it != vecAccount.end(); it++)
		printf("%s\n", it->c_str());

	return 0;
}

上例中用到了find_if函数，并自己指定predicate function（即find_if函数的第三个参数，请查阅STL手册）。

template<class InputIterator, class Predicate>

InputIterator find_if(InputIterator _First, InputIterator _Last, Predicate _Pred);

Parameters

_First

An input iterator addressing the position of the first element in the range

to be searched.

_Last

An input iterator addressing the position one past the final element in the

range to be searched.

_Pred

User-defined predicate function object that defines the condition to be

satisfied by the element being searched for. A predicate takes single argument

and returns true or false.