代码题：使用vector实现一个简单的本地注册登录系统
    注册：将账号密码存入vector里面，注意防重复判断
    登录：判断登录的账号密码是否正确

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sstream>
#include <vector>
#include <memory>using namespace std;struct uses
{string usename;string useid;
};class Stu{
private:public:                                                                              };template<typename T>
typename vector<T>::iterator find_ele(vector<T>& v,T ele)
{typename vector<T>::iterator it=v.begin();for(it;it!=v.end();it++){if(it->usename==ele.usename&&it->useid==ele.useid){return it;}}return v.end();
}
//查找int main(int argc,const char** argv){vector<struct uses> v;cout << "请输入:" <<endl;cout << "1:注册" <<endl;cout << "2：登录:" <<endl;int choose;cin >>choose;struct uses use;switch(choose){case 1:cout << "请输入账户:" <<endl;cin>>use.usename;cout << "请输入密码:" <<endl;cin>>use.useid;if(find_ele(v,use)!=v.end()){v.push_back(use);cout<<"注册成功"<<endl;}elsecout<<"该账户已被注册"<<endl;break;case 2:cout << "请输入账户:" <<endl;cin>>use.usename;cout << "请输入密码:" <<endl;cin>>use.useid;if(find_ele(v,use)!=v.end()){cout<<"账号密码正确，登录成功"<<endl;}elsecout<<"输入错误"<<endl;break;}
}