set容器

	所有元素都会在插入时，自动被排序。set/multset属于关联式容器，底层结构式用二叉树实现的。set容器不允许有重复的元素；multset容器允许有重复的元素。

1.构造和赋值

/*1.插入 - insert*/
/*2.拷贝构造*/
/*3.赋值 - operator= */

代码工程

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<set>using namespace std;/*1.插入 - insert*/
/*2.拷贝构造*/
/*3.赋值 - operator= */
void printSet(const set<int>&s)
{for (set<int>::const_iterator it = s.begin(); it != s.end(); it++){cout << *it << " ";}cout << endl;
}void test01()
{set<int>s;/*1.插入 - insert  插入数据只有insert方式*/s.insert(20);s.insert(30);s.insert(10);s.insert(40);/*无序插入，输出打印还是有序排列的*/printSet(s);/*2.拷贝构造*/set<int>s1(s);printSet(s1);/*3.赋值  operator= */set<int>s2;s2 = s1;printSet(s2);return;
}int main()
{test01();return 0;
}

运行结果

2.大小和交换

/*1.判断大小 - size*/
/*2.判断是否为空 - empty*/
/*3.交换容器 - swap */

代码工程

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<set>using namespace std;/*1.判断大小 - size*/
/*2.判断是否为空 - empty*/
/*3.交换容器 - swap */
void printSet(const set<int>& s)
{for (set<int>::const_iterator it = s.begin(); it != s.end(); it++){cout << *it << " ";}cout << endl;
}void test01()
{set<int>s;s.insert(20);s.insert(30);s.insert(10);s.insert(40);printSet(s);if (0 != s.empty()){cout << "容器为空" << endl;return;}cout << "容器的大小：" << s.size() << endl;set<int>s1;s1.insert(200);s1.insert(300);s1.insert(100);s1.insert(400);cout << endl;cout << "交换两个容器的元素" << endl;cout << "交换前s容器元素：" << "\t";printSet(s);cout << "交换前s1容器元素：" << "\t";printSet(s1);s.swap(s1);cout << "交换后s容器元素：" << "\t";printSet(s);cout << "交换后s1容器元素：" << "\t";printSet(s1);return;
}int main()
{test01();return 0;
}

运行结果

4.插入和删除

/*1.插入数据 - insert*/
/*2.删除数据 - erase*/
/*3.清空数据 - clear*/

代码工程

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<set>using namespace std;/*1.插入数据 - insert*/
/*2.删除数据 - erase*/
/*3.清空数据 - clear*/void printSet(const set<int>& s)
{for (set<int>::const_iterator it = s.begin(); it != s.end(); it++){cout << *it << " ";}cout << endl;
}void test01()
{set<int>s;/*1.插入数据 - insert*/s.insert(20);s.insert(30);s.insert(10);s.insert(40);printSet(s);/*2.删除数据 - erase*/s.erase(s.begin());printSet(s);/*删除 - 重载版本*/s.erase(40);printSet(s);/*3.清空 - clear*/s.clear();//erase(s.begin(), s.end());printSet(s);if (0 == s.empty()){cout << "容器不为空" << endl;}else{cout << "容器为空" << endl;}return;
}int main()
{test01();return 0;
}

运行结果

5.查找和统计

/*1.查找数据 - find*/
/*2.统计个数 - count*/

工程代码

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<set>using namespace std;/*1.查找数据 - find*/
/*2.统计个数 - count*/void printSet(const set<int>& s)
{for (set<int>::const_iterator it = s.begin(); it != s.end(); it++){cout << *it << " ";}cout << endl;
}void test01()
{set<int>s;s.insert(20);s.insert(30);s.insert(10);s.insert(40);printSet(s);set<int>::iterator pos = s.find(30);if (s.end() == pos){cout << "没找到元素" << endl;}else{cout << *pos << endl;/*set容器统计个数要么是0，要么是1*/cout << "统计元素是20的个数：" << s.count(20) << endl;}return;
}int main()
{test01();return 0;
}

运行结果

6.multset

	multset可以插入重复的元素

代码工程

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<set>using namespace std;void printMultset(const multiset<int>&ms)
{for (multiset<int>::const_iterator it = ms.begin(); it != ms.end(); it++){cout << *it << " ";}cout << endl;
}void test01()
{multiset<int>ms;/*可以插入重复的元素*/ms.insert(20);ms.insert(30);ms.insert(30);ms.insert(10);printMultset(ms);return;
}int main()
{test01();return 0;
}

运行结果

7.指定排序规则

代码工程

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<set>using namespace std;class MyCmp
{
public:/*仿函数后边加入，const*/bool operator()(int v1, int v2) const{return v1 > v2;}
};void printSet(set<int, MyCmp>& s)
{for (set<int, MyCmp>::iterator it = s.begin(); it != s.end(); it++){cout << *it << " ";}cout << endl;
}void test01()
{set<int, MyCmp>s;s.insert(20);s.insert(30);s.insert(10);s.insert(40);printSet(s);return;
}int main()
{test01();return 0;
}

运行结果

8.自定义数据类型排序

代码工程

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<string>
#include<set>using namespace std;class Person
{
public:Person(string name, int age){my_name = name;my_age = age;}string my_name;int my_age;
};class MyCmp
{
public:bool operator()(Person p1, Person p2) const{if (p1.my_age > p2.my_age){return true;}else{return false;}}
};void printSet(set<Person, MyCmp>&s)
{for (set<Person, MyCmp>::iterator it = s.begin(); it != s.end(); it++){cout << "姓名：" << it->my_name << "\t" << "年龄" << it->my_age << endl;}
}void test01()
{Person p1("曹操", 28);Person p2("刘备", 30);Person p3("赵云", 35);set<Person, MyCmp>s;s.insert(p1);s.insert(p2);s.insert(p3);printSet(s);return;
}int main()
{test01();return 0;
}

运行结果