STL 中的SET使用方法

#include <iostream>


#include <string>


#include <set>




using namespace std;




struct strLess


{


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


{


return strcmp(s1, s2) < 0;


}


};




void printSet(set<int> s)


{


copy(s.begin(), s.end(), ostream_iterator<int>(cout, ", ") );




// set<int>::iterator iter;


// for (iter = s.begin(); iter != s.end(); iter++)


// //cout<<"set["<<iter-s.begin()<<"]="<<*iter<<", "; //Error


// cout<<*iter<<", ";


cout<<endl;


}




void main()


{


//创建set对象，共5种方式，提示如果比较函数对象及内存分配器未出现，即表示采用的是系统默认方式


//创建空的set对象，元素类型为int，


set<int> s1;


//创建空的set对象，元素类型char*，比较函数对象(即排序准则)为自定义strLess


set<const char*, strLess> s2( strLess);


//利用set对象s1,拷贝生成set对象s2


set<int> s3(s1);


//用迭代区间[&first, &last)所指的元素，创建一个set对象


int iArray[] = {13, 32, 19};


set<int> s4(iArray, iArray + 3);


//用迭代区间[&first, &last)所指的元素，及比较函数对象strLess，创建一个set对象


const char* szArray[] = {"hello", "dog", "bird" };


set<const char*, strLess> s5(szArray, szArray + 3, strLess() );




//元素插入：


//1,插入value，返回pair配对对象，可以根据.second判断是否插入成功。(提示:value不能与set容器内元素重复)


//pair<iterator, bool> insert(value)


//2,在pos位置之前插入value，返回新元素位置，但不一定能插入成功


//iterator insert(&pos, value)


//3,将迭代区间[&first, &last)内所有的元素，插入到set容器


//void insert[&first, &last)


cout<<"s1.insert(

) : "<<endl;


for (int i = 0; i <5 ; i++)


s1.insert(i*10);


printSet(s1);




cout<<"s1.insert(20).second = "<<endl;;


if (s1.insert(20).second)


cout<<"Insert OK!"<<endl;


else


cout<<"Insert Failed!"<<endl;




cout<<"s1.insert(50).second = "<<endl;


if (s1.insert(50).second)


{cout<<"Insert OK!"<<endl; printSet(s1);}


else


cout<<"Insert Failed!"<<endl;




cout<<"pair<set<int>::iterator::iterator, bool> p;\np = s1.insert(60);\nif (p.second):"<<endl;


pair<set<int>::iterator::iterator, bool> p;


p = s1.insert(60);


if (p.second)


{cout<<"Insert OK!"<<endl; printSet(s1);}


else


cout<<"Insert Failed!"<<endl;




//元素删除


//1,size_type erase(value) 移除set容器内元素值为value的所有元素，返回移除的元素个数


//2,void erase(&pos) 移除pos位置上的元素，无返回值


//3,void erase(&first, &last) 移除迭代区间[&first, &last)内的元素，无返回值


//4,void clear()， 移除set容器内所有元素




cout<<"\ns1.erase(70) = "<<endl;


s1.erase(70);


printSet(s1);


cout<<"s1.erase(60) = "<<endl;


s1.erase(60);


printSet(s1);




cout<<"set<int>::iterator iter = s1.begin();\ns1.erase(iter) = "<<endl;


set<int>::iterator iter = s1.begin();


s1.erase(iter);


printSet(s1);




//元素查找


//count(value)返回set对象内元素值为value的元素个数


//iterator find(value)返回value所在位置，找不到value将返回end()


//lower_bound(value),upper_bound(value), equal_range(value) 略


cout<<"\ns1.count(10) = "<<s1.count(10)<<", s1.count(80) = "<<s1.count(80)<<endl;


cout<<"s1.find(10) : ";


if (s1.find(10) != s1.end())


cout<<"OK!"<<endl;


else


cout<<"not found!"<<endl;




cout<<"s1.find(80) : ";


if (s1.find(80) != s1.end())


cout<<"OK!"<<endl;


else


cout<<"not found!"<<endl;




//其它常用函数


cout<<"\ns1.empty()="<<s1.empty()<<", s1.size()="<<s1.size()<<endl;


set<int> s9;


s9.insert(100);


cout<<"s1.swap(s9) :"<<endl;


s1.swap(s9);


cout<<"s1: "<<endl;


printSet(s1);


cout<<"s9: "<<endl;


printSet(s9);


//lower_bound,upper_bound,equal_range(略)


}






///////////////i测试结果/////////////////////////


s1.insert(

) :


0, 10, 20, 30, 40,


s1.insert(20).second =


Insert Failed!


s1.insert(50).second =


Insert OK!


0, 10, 20, 30, 40, 50,


pair<set<int>::iterator::iterator, bool> p;


p = s1.insert(60);


if (p.second):


Insert OK!


0, 10, 20, 30, 40, 50, 60,




s1.erase(70) =


0, 10, 20, 30, 40, 50, 60,


s1.erase(60) =


0, 10, 20, 30, 40, 50,


set<int>::iterator iter = s1.begin();


s1.erase(iter) =


10, 20, 30, 40, 50,




s1.count(10) = 1, s1.count(80) = 0


s1.find(10) : OK!


s1.find(80) : not found!




s1.empty()=0, s1.size()=5


s1.swap(s9) :


s1:


100,


s9:


10, 20, 30, 40, 50,