#include <iostream>
// UNIQ

using namespace std;

struct stack {

public:
    int value;
    stack* next;

    stack();
    void print();
    void push(int i);
    bool is_empty();
    void delete_if(bool (*p)(stack*));
    void delete_all(bool (*p)(stack*));
    void delete_if_value(int value);
    stack* pop();
    stack* top();
    bool exists(int val);

};

int GLOBAL_VALUE=0;

stack::stack(){
    next = NULL;
    value = 0;
}

bool stack::is_empty(){
    return this->next == NULL ? true : false;
}

void stack::push(int i){
    stack* last = this->top();

    last->next = new stack();
    last->next->value = i;
}

stack* stack::pop(){

    stack* t = this;

    while(!this->is_empty()){

        if(t->next->next != NULL){
            t = t->next;
        } else {
            stack* obj = t->next;
            t->next = NULL;
            return obj;
        };

    }

    return NULL;
}

stack* stack::top(){
    stack* t = this;
    while(true){

        if(t->next != NULL){
            t = t->next;
        } else {
            break;
        };

    }
    return t;
}

void stack::print(){
    stack* t = this->next;
    while(!this->is_empty()){
        cout << t->value << endl;

        if(t->next != NULL){
            t = t->next;
        } else {
            break;
        };

    }
}

void stack::delete_if_value(int value){
    stack* t = this->next;
    stack* prev = this;
    while(!this->is_empty()){

        if(t->value == value){
            prev->next = t->next;
        }else{
            prev=t;
        }


        if(t->next!=NULL){
            t = t->next;
        } else {
            break;
        };

    }
}


void stack::delete_if(bool (*p)(stack* el)){
    stack* t = this->next;
    stack* prev = this;
    while(!this->is_empty()){

        if((*p)(t)){
            prev->next = t->next;
        }else{
            prev=t;
        }


        if(t->next!=NULL){
            t = t->next;
        } else {
            break;
        };

    }
}

void stack::delete_all(bool (*p)(stack* el)){
    stack* t = this->next;
    stack* prev = this;
    while(!this->is_empty()){

        if((*p)(t)){
            t->delete_if_value(t->value);
            prev->next = t->next;
        }else{
            prev=t;
        }

        if(t->next!=NULL){
            t = t->next;
        } else {
            break;
        };

    }
}


bool stack::exists(int value){

    stack* t = this->next;
    if(this->is_empty()) return false;
    while(true){

        if(t->value == value){
            return true;
        }

        if(t->next != NULL){
            t = t->next;
        } else {
            break;
        };

    }

    return false;
}

bool condition(stack* s){
    return s->exists(s->value);
}

int main()
{
    int s;
    stack a;

    cout << "Enter size: " << endl;
    cin >> s;

    for(int i=0; i<s; i++){
        cout << "Enter element #"<< i<< endl;
        int tmp;
        cin >> tmp;
        a.push(tmp);
    }

    cout << "--------------------" << endl;
    a.print();

    a.delete_all(condition);
    cout << "--------------------" << endl;
    a.print();

    return 0;
}