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;
    }
    else
        cout<<"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;
    }
    else
        cout<<"输入错误"<<endl;
    break;
    }
}