c++ stl algorithm: std::find, std::find_if

时间：2015-08-13 20:36:12 阅读：134 评论：0 收藏：0 [点我收藏+]

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td::find:

查找容器元素, find只能查找容器元素为<基本数据类型>

[cpp] view plain copy

#include <iostream>
#include <vector>
#include <algorithm>
int main()
{
std::vector<int> v;
for (int i = 0; i < 10; ++i)
v.push_back(i);
std::vector<int>::iterator iter = std::find(v.begin(), v.end(), 3);
if (iter == v.end())
std::cout << "can not find value 3 in v" << std::endl;
else
std::cout << "the index of value " << (*iter) << " is " << std::distance(v.begin(), iter) << std::endl;
return 0;
}

std::find_if

按条件查找容器元素, 容器类型为<类>时, 无法使用find来查找, 所以要使用find_if来查找

[cpp] view plain copy

#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
struct Point
{
int x;
int y;
};
struct PointFindByCoord : public std::binary_function<Point, Point, bool>
{
bool operator () (const Point &obj1, const Point &obj2) const
{
return obj1.x == obj2.x && obj1.y == obj2.y;
}
};
int main()
{
std::vector<Point> v;
for (int i = 0; i < 5; ++i)
{
for (int j = 0; j < 5; ++j)
{
Point pt;
pt.x = i;
pt.y = j;
v.push_back(pt);
}
}
Point needFind;
needFind.x = 4;
needFind.y = 3;
std::vector<Point>::iterator iter = std::find_if(v.begin(), v.end(), std::bind2nd(PointFindByCoord(), needFind));
if (iter == v.end())
{
// 未找到
}
else
std::cout << "the index of value Point(" << (*iter).x << ", " << (*iter).y
<< ") is " << std::distance(v.begin(), iter) << std::endl;
return 0;
}

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