stack

#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>

using namespace std;

ifstream in("input.txt");
ofstream out("output.txt");

class Stack {
    struct slovos {
        string wrd;
        slovos *next;
        slovos(string x, slovos *p) : wrd(x), next(p){}
    };
    slovos* head;
public:
    Stack() : head(0){}
    bool Empty() { //проверка на пустоту стека
        return head == 0;
    }
    void Push(string data) { // добавляем элемент
        head = new slovos(data, head);
    }
    string Top() {
        return head->wrd;
    }
    string Pop() {
        slovos* r = head;
        string i = r->wrd;
        head = r->next;
        delete r;
        return i;
    }

};

int main() {
    Stack t, t1;
    string s;
    while (in >> s) {
        t.Push(s);
    }
    in.close();

    while (!t.Empty()) {
        string i = t.Pop();
        t1.Push(i);
        if (i.size() == 1) {
            t1.Push(i);
        }
    }

    while (!t1.Empty()) {
        out << t1.Pop() << endl;
    }
    out.close();

    return 0;
}