20.cpp

这是一些c++例程

// 20.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <algorithm>
#include <list>
#include <set>
#include <deque>

using namespace std;

// 假设您需要将指向类X的对象的指针放入STL容器。
class X
{
public:
	int I;
	
public:
	//构造函数，拷贝构造函数，析构函数
	X(int i) : I(i) {}
	X(const X& x) : I(x.I) {}
	~X() {delete this;}
	//重载运算符= ,()
	X& operator= (const X& x) { I = x.I; }
	int operator()() const { return I; }
};

// 定义一个用于STL容器的指针封装类
// 因为使用STL不宜直接向容器中添加指针。
class PtrWrapper 
{
public:
	 X* px;	//指向类X的指针
	
public:
	//构造及拷贝构造函数
	 PtrWrapper(X* x = 0) : px(x) {}
	 PtrWrapper(const PtrWrapper& pw) : px(pw.px) {}
	//析构函数
	 ~PtrWrapper() {}
	 PtrWrapper operator= (const PtrWrapper& pw) { px = pw.px; return pw;}
	 
	//重载运算符()返回对象X的指针
	 const X* operator() () const { return px; }
	 X* operator() () { return px; }
};

//重载逻辑运算符 == , < , >
bool operator== (const PtrWrapper& pw1, const PtrWrapper& pw2)
{
	return (pw1.operator()() && pw2.operator()()) ? pw1.px->I == pw2.px->I : false;
}

bool operator< (const PtrWrapper& pw1, const PtrWrapper& pw2) 
{
	return (pw1() && pw2()) ? pw1.px->I < pw2.px->I : false;
}

bool operator> (const PtrWrapper& pw1, const PtrWrapper& pw2) 
{
	return (pw1() && pw2()) ? !(pw1.px->I < pw2.px->I) : false;
}

//重载逻辑运算符
bool operator== (const X& x1, const X& x2)
{
	return x1() == x2();
}

bool operator< (const X& x1, const X& x2) 
{
	return x1() < x2();
}

void print(PtrWrapper myp)
{
	if(myp.px!=NULL)cout<<myp.px->I<<" ";
}

int main(int, char*[]) 
{
	PtrWrapper bucket[5];
	for(int i = 1; i < 6; ++i)
	{
		bucket[i] = PtrWrapper(new X(i * i));

		random_shuffle(bucket, bucket + 5);
	
		list<PtrWrapper> list1;
		copy(bucket, bucket + 5, back_insert_iterator<list<PtrWrapper> >(list1));
	
		cout << "List of PtrWrapper: ( ";
		for_each(list1.begin(), list1.end(), print);
		cout << ")" << endl;
	
		set<PtrWrapper, greater<PtrWrapper> > set1;
		copy(list1.begin(), list1.end(), insert_iterator<set<PtrWrapper, greater<PtrWrapper> > >(set1, set1.begin()));
	
		cout << "Set of PtrWrapper : [ ";
		for_each(set1.begin(), set1.end(), print);
		cout << "]" << endl;
	
		deque<PtrWrapper> deque1;
		copy(list1.begin(), list1.end(),
		back_insert_iterator<deque<PtrWrapper> > (deque1));
	
		cout << "Deque of PtrWrapper : ( ";
		for_each(deque1.begin(), deque1.end(), print);
		cout << ")\n" << endl;
	}
	return 0;
}