set用法

set是一种集合容器.-所以采用迭代器进行访问

作用：保证每个元素都是独一无二的；

应用：插入、遍历、删除、搜索；

eg:

#include<iostream>#include<string>#include<cstring>#include<cstdio>#include<cstdlib>#include<set>using namespace std;set<int>a;int main(){    int n,x;    while(cin>>n&&n)    {        //clear()清零
                  a.clear();   
                  //insert()插入
        for(int i=0;i<n;i++)        {            cin>>x;            a.insert(x);        }            int len=a.size();        //iterator()顺序遍历        cout<<"len:"<<len<<endl;        cout<<"顺序遍历"<<endl;        set<int>::iterator s;        for(s=a.begin();s!=a.end();s++)        cout<<*s<<" ";        cout<<endl;                //reverse_iterator()反向遍历        cout<<"反向遍历"<<endl;        set<int>::reverse_iterator t;        for(t=a.rbegin();t!=a.rend();t++)        cout<<*t<<" ";        cout<<endl;                //erase()删除        cout<<"please input the number that you want to delete:"<<endl;        int tx;        cin>>tx;        a.erase(tx);        set<int>::iterator s1;        for(s1=a.begin();s1!=a.end();s1++)            cout<<*s1<<" ";        cout<<endl;                //find()检索        cout<<"please input the number you want to find:"<<endl;        cin>>tx;        set<int>::iterator s2;        s2=a.find(tx);        if(s2!=a.end())            cout<<*s2<<endl;        else            cout<<"not find it!"<<endl;        system("cls");    }    }