#include <iostream>

using namespace std;

struct Vector
{ int * v;
  int size; // actual current size of the internal array
  int num;  // how many ints are actually stored in it

  Vector()   // no return type, same name as object = CONSTRUCTOR
  { size = 0;
    num = 0;
    v = new int[0]; }

  // Functions inside an object are called METHODS
  void setsize(int sz)
  { if (sz < 0)
    { cout << "Can't create an array of size " << sz << "\n";
      exit(1); }
    int * temp = new int[sz];
    int amt = min(size, sz);
    for (int i = 0; i < amt; i += 1)
      temp[i] = v[i];
    delete v;  // without this we had a MEMORY LEAK
    v = temp;
    size = sz; }

  int getsize()
  { return size; }

  int & access(int pos)
  { if (pos < 0)
    { cout << "Index to array is out of bounds\n";
      exit(1); }
    if (pos >= size)
      setsize(pos + 1);
    return v[pos]; }

  void push(int x)
  { access(num) = x;
    num += 1; }

  int pop()                 // adding push and pop makes this vector into a STACK
  { num -= 1;
    return access(num); }
};

bool looks_like_an_int(string s)
{ for (int i = 0; i < s.length(); i += 1)
    if (s[i] < '0' || s[i] > '9')
      return false;
  return true; }

int convert_string_to_int(string s)
{ int sofar = 0;
  for (int i = 0; i < s.length(); i += 1)
    sofar = sofar * 10 + s[i] - '0';
  return sofar; }

struct Input
{ string s;
  int pos;

  Input(string x)
  { s = x + " ";
    pos = 0; }

  void take(string x)
  { s = x + " ";
    pos = 0; }

  string get()
  { // example:
    // s = "1 x 7363 * + ."
    // pos = 3
    while (s[pos] == ' ')
      pos += 1;
    string result = "";
    while (s[pos] != ' ')
    { result += s[pos];
      pos += 1; }
    return result; }
};

void evaluate(string formula, int x)
{ Input in(formula);
  Vector R;
  while (true)
  { string part = in.get();

    if (part == "x")
      R.push(x);

    else if (part == ".")
    { cout << "Result is " << R.pop() << "\n";
      break; }

    else if (looks_like_an_int(part))
      R.push(convert_string_to_int(part));

    else if (part == "+")
    { int second = R.pop();
      int first = R.pop();
      R.push(first + second); }

    else if (part == "-")
    { int second = R.pop();
      int first = R.pop();
      R.push(first - second); }

    else if (part == "*")
    { int second = R.pop();
      int first = R.pop();
      R.push(first * second); }

    else if (part == "/")
    { int second = R.pop();
      int first = R.pop();
      if (second == 0)
      { cout << "division by zero\n";
        exit(1); }
      R.push(first / second); }

    else
    { cout << "error '" << part << "' in formula\n";
      exit(1); } } }

int main()
{ cout << "Enter a range for x: ";
  int xmin, xmax;
  cin >> xmin >> xmax;
  cout << "Enter the formula: ";
  string formula;
  getline(cin, formula);  // to absorb the enter after x
  getline(cin, formula);
  for (int x = xmin; x <= xmax; x += 1)
    evaluate(formula, x); }