Тестовое задание

#include <iostream>
#include <conio.h>
#include <string>
#include <set>
#include <map>
#include <algorithm>
#include <string>
#include <math.h>
#include <vector>

using namespace std;

struct profil
{
    string name, password;
};

bool operator==(profil data1, profil data2)
{
    return data1.name == data2.name;
}

bool findbool(vector <profil> data, string name)
{
    auto i = data.begin();
    bool p = false;
    for (i; i != data.end(); i++)
    {
        if (i->name == name)
        {
            p = true;
            break;
        }
    }
    return p;
}

bool findboolstr(vector <string> data, string name)
{
    bool p = false;
    auto i = data.begin();
    for (i; i != data.end(); i++)
    {
        if (*i == name)
        {
            p = true;
            break;
        }
    }
    return p;
}

vector<profil>::iterator find(vector <profil> &data, string name)
{
    auto i = data.begin();
    for (i; i != data.end(); i++)
    {
        if (i->name == name)
        {
            break;
        }
    }

    return i;
}

vector<string>::iterator findstr(vector <string> &data, string name)
{
    auto i= data.begin();
    for (i; i != data.end(); i++)
    {
        if (*i == name)
        {
            break;
        }
    }
    return i;
}

vector<profil> reg(vector<profil> data)
{
    string name, password;
    cin >> name >> password;

    if (findbool(data, name))
    {
        cout << "fail: user already exists" << endl;
        return data;
    }
    else
    {
        profil prom;
        prom.name = name;
        prom.password = password;
        data.push_back(prom);
        cout << "success: new user added" << endl;
        return data;
    }
}

vector <string> login(vector<profil> data, vector <string> online)
{
    string name, password;
    auto num = data.begin();
    cin >> name >> password;

    if (findbool(data, name))
    {
        num = find(data, name);
        if (num->password == password)
        {
            if (findboolstr(online, name))
            {
                cout << "fail: already logged in" << endl;
                return online;
            }
            else
            {
                cout << "success: user logged in" << endl;
                online.push_back(name);
                return online;
            }
        }
        else
        {
            if (num->password != password)
            {
                cout << "fail: incorrect password" << endl;
                return online;
            }
            else
                if (findboolstr(online, name))
                {
                    cout << "fail: already logged in" << endl;
                    return online;
                }
        }

    }
    else
    {
        cout << "fail: no such user" << endl;
        return online;
    }
}

vector <string> logout(vector<profil> data, vector <string> online)
{
    string name;
    auto num = online.begin();
    cin >> name;
    if(findbool(data, name))
        if (findboolstr(online, name))
        {
            num = findstr(online, name);
            online.erase(num);
            cout << "success: user logged out" << endl;
            return online;
        }
        else
        {
            cout << "fail: already logged out" << endl;
            return online;
        }
    else
    {
        cout << "fail: no such user" << endl;
        return online;
    }
}

int main()
{
    vector <string> online;
    vector <profil> data;
    string comand;
    int n;

    cin >> n;

    for (int i = 1; i <= n; i++)
    {
        cin >> comand;
        if (comand == "register")
            data = reg(data);
        else
            if (comand == "login")
                online = login(data, online);
            else
                online = logout(data, online);
    }

    _getch();
    return 0;
}