Bidirectional dynamic list

#include<iostream>
#include<vector>
#include <functional>
#include<string>
#include<algorithm>
#include <tuple>
#include<random>
#include <iomanip>
#include <iterator>
#include<set>
#include<map>
#include<string>
using namespace std;
random_device r;
struct  List {
    int number;
    string date;
    int code;
    List* priv = nullptr;
    List* next = nullptr;
    List(const int&, string, const int&);
    List(const int&);
    List(const List&);
};
void outputfr(List*);

void outputbh(List*);

void insert(List* , const int&, string, const int&);

void eraze(List* , const int&);

List& moving(List* );

void quantity(List* );

int main() {

    List p(3);   // создание и ожидание ввода 3 элементов (сначала вводится Номер мед. полиса, потом  Дата обращения, после Код диагноза)
    outputfr(&p); // вывод от первого к последнему
    outputbh(&p); // вывод от последнего к первому
    insert(&p, 2, "7 November", 6); //вставка нового узла
    outputfr(&p);
    eraze(&p, 1); // удаление всех узлов с заданным значением кода диагноза
    outputfr(&p);
    List q = moving(&p);  // перемещение всех узлов с одинаковым мед. полисом
    outputfr(&q);
    quantity(&p); //Определение  количества обращений в одну и туже дату содним и тем же диагнозом и вывод
}
List::List(const int& p, string s, const int& o) {
    number = p;
    date = s;
    code = o;
}
List::List(const int& a) {
    List* w = this;
    List* q = nullptr;
    int p, o; string s;
    cin >> p >> s >> o;
    this->number = p;
    this->date = s;
    this->code = o;
    for (int i = 0; i < a - 1; ++i) {
        cin >> p >> s >> o;
        w->next = new List(p, s, o);
        q = w;
        w = w->next;
        w->priv = q;
    }
    w->next = this;
    this->priv = w;

}
List::List(const List& p) {
        this->next = p.next;
        this->priv = p.priv;
        this->code = p.code;
        this->date = p.date;
        this->number = p.number;
        this->next->priv = this;
        this->priv->next = this;
        delete& p;
}
void outputfr(List* s) {
    List* q = s;
    while (1) {
        cout << s->number << ' ' << s->date << ' ' << s->code << "     ";
        s = s->next;
        if (s == q)break;
    }
    cout << '\n';
}
void outputbh(List* s) {
    s = s->priv;
    List* q = s;
    while (1) {
        cout << s->number << ' ' << s->date << ' ' << s->code << "     ";
        s = s->priv;
        if (s == q)break;
    }
    cout << '\n';
}
void insert(List* s, const int& a, string u, const int& p) {
    List* w = s;
    List* f = s;
    if (w->number == a) {
        w = new List(a, u, p);
        w->next = s->next;
        s->next->priv = w;
        s->next = w;
        w->priv = s;
        swap(w->code, s->code);
        swap(w->date, s->date);
        return;
    }
    s = s->next;
    while (s != f) {
        if (s->number == a) {
            List* q = new List(a, u, p);
            s->priv->next = q;
            q->priv = s->priv;
            q->next = s;
            s->priv = q;
            return;
        }
        if (s == f->priv) {
            List* q = new List(a, u, p);
            s->next = q;
            q->priv = s;
            q->next = f;
            f->priv = q;
            return;
        }
        s = s->next;
    }
}
void eraze(List* s, const int& p) {
    List* q = s;
    List* f = s;
    vector<tuple<int, string, int>>v;
    do {
        if (s->code != p)
            v.push_back({ s->number,s->date,s->code });
        s = s->next;
    } while (s != f);
    s = q;
    int i = 0;
    do {
        if (i >= v.size()) {
            s = s->next;
            delete s->priv;
            continue;
        }
        s = s->next;
        ++i;
    } while (s != f);
    s = q;
    for (int i = 0; i < v.size(); ++i) {
        s->number = get<0>(v[i]);
        s->date = get<1>(v[i]);
        s->code = get<2>(v[i]);
        if (i + 1 == v.size()) {
            s->next = q;
            q->priv = s;
        }
        s = s->next;
    }
}
List& moving(List* s) {
    map<int, vector<pair<string, int>>>m;
    List* f = s;
    do {
        if (m.find(s->number) == m.end())
            m.insert({ s->number,{} });
        m[s->number].push_back({ s->date,s->code });
        s = s->next;
    } while (s != f);
    List* q = nullptr; List* w = nullptr; List* z;
    bool d = 0;
    for (auto& a : m) {
        if (a.second.size() > 1) {
            for (auto& b : a.second) {
                if (!d) {
                    q = new List(a.first, b.first, b.second);
                    d = 1;
                    w = q;
                    continue;
                }
                w->next = new List(a.first, b.first, b.second);
                z = w;
                w = w->next;
                w->priv = z;
            }
        }
    }
    if (q != nullptr && w != nullptr) {
        w->next = q;
        q->priv = w;
    }
    return *q;

}
void quantity(List* s) {
    List* f = s;
    map<string, map<int, int>>m;
    map<int, int>j;
    do {
        auto a = m.find(s->date);
        if (a == m.end()) {
            j.insert({ s->code,1 });
            m.insert({ s->date,j });
            j.clear();
        }
        else {
            if ((*a).second.find(s->code) == (*a).second.end())
                (*a).second.insert({ s->code,1 });
            else
                ++(*a).second.find(s->code);
        }
        s = s->next;
    } while (s != f);
    for (auto& a : m) {
        cout << "Date: " << a.first << '\n';
        cout << "   " << "Diagnosis code : number" << '\n';
        for (auto& b : a.second)
            cout << "   " << setw(14) << b.first << " : " << b.second << '\n';
    }
}