15.STL-适配器

• 适配器

• 函数对象适配器

• //1、利用bind2nd 进行绑定
• //2、继承 public binary_function<参数1 类型,参数2类型,返回值类型>
• //3、加const

• 取反适配器

• 一元取反 not1

• //1、利用not1进行取反
• //2、继承 public unary_function<int,bool>
• //3、加const

• 二元取反 not2

• 函数指针适配器

• ptr_fun将普通函数指针 适配成函数对象

• 成员函数适配器

• 如果存放的是对象实体 mem_fun_ref
• 如果存放的是对象指针 mem_fun

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

class MyPrint :public binary_function<int,int,void>
{
public:
	void operator()(int val , int start)const 
	{
		cout << "val = " << val << " start = " << start <<  " sum = " <<val +  start << endl;
	}
};
//1、函数对象适配器
void test01()
{
	vector<int>v;

	for (int i = 0; i < 10;i++)
	{
		v.push_back(i);
	}
	cout << "请输入起始累加值： " << endl;
	int num;
	cin >> num;

	for_each(v.begin(), v.end(), bind2nd( MyPrint(), num ) );
	//for_each(v.begin(), v.end(), bind1st(MyPrint(), num));
}

//1、利用bind2nd 进行绑定
//2、继承 public binary_function<参数1 类型,参数2类型,返回值类型>
//3、加const


//2、取反适配器
class GreaterThanFive:public unary_function<int,bool>
{
public:
	bool operator()(int val) const
	{
		return val > 5;
	}
};
void test02()
{
	vector<int>v;
	for (int i = 0; i < 10;i++)
	{
		v.push_back(i);
	}

	//一元取反
	//vector<int>::iterator pos = find_if(v.begin(), v.end(), not1( GreaterThanFive()));

	vector<int>::iterator pos = find_if(v.begin(), v.end(), not1( bind2nd( greater<int>() , 5 )));

	if (pos != v.end())
	{
		cout << "找到小于5的值为： " << *pos << endl;
	}
	else
	{
		cout << "未找到" << endl;
	}


	//二元取反
	sort(v.begin(), v.end(),  not2 (less<int>()));
	for_each(v.begin(), v.end(), [](int val){cout << val << endl; });
}

//1、利用not1进行取反
//2、继承 public unary_function<int,bool>
//3、加const


void myPrint3( int val , int start) 
{
	cout << val + start << endl;
}
//3、 函数适配器
void test03()
{
	vector<int>v;

	for (int i = 0; i < 10; i++)
	{
		v.push_back(i);
	}
	//将函数指针 适配成函数对象  ptr_fun
	for_each(v.begin(), v.end(), bind2nd(ptr_fun(myPrint3), 1000));
}


//4、成员函数适配器
class Person
{
public:
	Person(string name, int age)
	{
		this->m_Name = name;
		this->m_Age = age;
	}

	void showPerson()
	{
		cout << "成员函数----姓名： " << this->m_Name << " 年龄： " << this->m_Age << endl;
	}

	void addAge()
	{
		this->m_Age += 100;
	}

	string m_Name;
	int m_Age;
};

//void myPrint4( Person & p)
//{
//	cout << "姓名： " << p.m_Name << " 年龄： " << p.m_Age << endl;
//}

void test04()
{
	vector< Person > v;

	Person p1("aaa", 10);
	Person p2("bbb", 20);
	Person p3("ccc", 30);
	Person p4("ddd", 40);
	v.push_back(p1);
	v.push_back(p2);
	v.push_back(p3);
	v.push_back(p4);
	//利用 mem_fun_ref
	for_each(v.begin(), v.end(),  mem_fun_ref(&Person::showPerson));
	for_each(v.begin(), v.end(), mem_fun_ref(&Person::addAge));
	for_each(v.begin(), v.end(), mem_fun_ref(&Person::showPerson));
}

int main(){

//	test01();
//	test02();
//	test03();
	test04();

	system("pause");
	return EXIT_SUCCESS;
}