#include <iostream>
#include <string>
#include <cassert>

using namespace std;

struct person
{ string name, phone;

  person(string n, string p)
  { name = n;
    phone = p; } };

class vec
{ protected:
    person * * data;
    int capacity;
    int number;

  public:
    vec(int sz = 0)
    { data = new person * [sz];
      capacity = sz;
      number = 0; }

    void push_back(person * p)
    { if (number == capacity)
      { int newcap = capacity * 2;
        if (newcap <= capacity)
          newcap = capacity + 1;
        grow_to(newcap); }
      data[number] = p;
      number += 1; }

    person * pop_back()
    { assert(number > 0);
      number -= 1;
      return data[number]; }

    void grow_to(int newcap)
    { if (newcap <= capacity)
        return;
      person * * newdata = new person * [newcap];
      for (int i = 0; i < number; i += 1)
        newdata[i] = data[i];
      delete [] data;
      data = newdata;
      capacity = newcap; }

    void shrink_to(int newcap)
    { if (newcap >= capacity)
        return;
      person * * newdata = new person * [newcap];
      for (int i = 0; i < min(number, newcap); i += 1)
        newdata[i] = data[i];
      delete [] data;
      data = newdata;
      capacity = newcap; } };

int main()
{ vec V;
  V.push_back(new person("J Smith", "1234567890"));
  V.push_back(new person("F Jones", "9876543210"));
  V.push_back(new person("P Ratbag", "1111111111"));
  person * x;
  x = V.pop_back();
  cout << x->name << " " << x -> phone << "\n";
  x = V.pop_back();
  cout << x->name << " " << x -> phone << "\n";
  x = V.pop_back();
  cout << x->name << " " << x -> phone << "\n"; }