STL中的set集合容器进行集合运算：并、交、差实例

集合容器的集合运算：并、交、差：

#include "stdafx.h"

#include <iostream>

#include <set>

#include <algorithm> //集合运算：并、交、差需要包含该头文件

using namespace std;

structltstr

{

    bool operator()(const char* s1,const char* s2) const

    {

       return strcmp(s1,s2)<0; //由小到大排序

//return strcmp(s1,s2)<0; //由大到小排序

    }

};

int_tmain(int argc, _TCHAR* argv[])

{

const int N = 6;

    const char* a[N] = {"isomer","ephemeral","prosaic","nugatory","artichoke","serif"};

    const char* b[N] = {"flat","this","artichoke","frigate","prosaic","isomer"};

    set<const char*,ltstr>A(a,a+N);

    set<const char*,ltstr> B(b,b+N);

    set<const char*,ltstr>C;

    set<const char*,ltstr>D;

    cout<<"Set A:";

    copy(A.begin(),A.end(),ostream_iterator<const char*>(cout," "));

    cout<<endl;

    cout<<"Set B:";

    copy(B.begin(),B.end(),ostream_iterator<const char*>(cout," "));

    cout<<endl;

    cout<<"Union: ";

    //set_union函数需要#include <algorithm>

    set_union(A.begin(),A.end(),B.begin(),B.end(),ostream_iterator<const char*>(cout," "),ltstr());

    cout<<endl;

    cout<<"Intersection: ";

    set_intersection(A.begin(),A.end(),B.begin(),B.end(),ostream_iterator<const char*>(cout," "),ltstr());

    cout<<endl;

    cout<<"Set C (difference of A and B):";

    set_difference(A.begin(),A.end(),B.begin(),B.end(),inserter(C,C.begin()),ltstr());//从A中减去B包含的元素

    copy(C.begin(),C.end(),ostream_iterator<const char*>(cout," "));

    cout<<endl;

    cout<<"Set D (difference of B and A):";

    set_difference(B.begin(),B.end(),A.begin(),A.end(),inserter(D,D.begin()),ltstr());//从B中减去A包含的元素

    copy(D.begin(),D.end(),ostream_iterator<const char*>(cout," "));

    cout<<endl;

    return 0;

}

运行结果：