集合运算样例

集合运算中的差集、交集、并集运算，set_difference，set_intersection、set_union

让人疑惑的是并不用集合，而是用向量计算。

// setSub.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{	
	vector<int> s1;
	vector<int> s2;
	vector<int> s3;	

	s1.push_back(1);
	s1.push_back(2);
	s2.push_back(1);

	//差集
	s3.resize(6,-1);
	set_difference(s1.begin(),s1.end(),s2.begin(),s2.end(),s3.begin());	
	//删除-1
	s3.erase(remove(s3.begin(),s3.end(),-1),s3.end());
	copy(s3.begin(),s3.end(),ostream_iterator<int>(cout," "));
    cout<<endl;

	//交集
	s3.resize(6,-1);
	set_intersection(s1.begin(),s1.end(),s2.begin(),s2.end(),s3.begin());
	//删除0
	s3.erase(remove(s3.begin(),s3.end(),-1),s3.end());
	copy(s3.begin(),s3.end(),ostream_iterator<int>(cout," "));
	cout<<endl;

	//并集
	s3.resize(6,-1);
	set_union(s1.begin(),s1.end(),s2.begin(),s2.end(),s3.begin());
	//删除0
	s3.erase(remove(s3.begin(),s3.end(),-1),s3.end());
	copy(s3.begin(),s3.end(),ostream_iterator<int>(cout," "));	

	getchar();
	return 0;
}