#include <iostream.h>
#include "dice.h"

// simluate one-dimensional random walk
// Owen Astrachan, 8/13/94

class RandomWalk
{
  public:
    RandomWalk(int maxSteps);  // constructor, parameter = max # steps
    void First();              // take first step of walk
    bool IsDone();             // returns true if walk finished, else false
    void Next();               // take next step of random walk

    void Display();            // current status of walk displayed
    int GetPosition();         // returns position (x coord) of frog
    int GetSteps();            // returns # of steps taken by frog
  private:
    void TakeStep();           // simulate one step of walk
    int myPosition;            // current x coordinate
    int mySteps;               // # of steps taken
    int myMaxSteps;            // maximum # of steps allowed
    Dice myCoin;               // 2-sided "die" for simulation
};

RandomWalk::RandomWalk(int maxSteps) : myCoin(2)
// postcondition: all private data fields initialized     
{
    myPosition = 0;
    mySteps = 0;
    myMaxSteps = maxSteps;
}

void RandomWalk::TakeStep()
// postcondition: one step of random walk taken
{
    switch (myCoin.Roll())
    {
      case 1:
        myPosition--;
        break;
      case 2:
        myPosition++;
        break;
    }
    mySteps++;
}

void RandomWalk::First()
// postcondition: first step of random walk taken
{
    myPosition = 0;
    mySteps = 0;
    TakeStep();
}

bool RandomWalk::IsDone()
// postcondition: returns true when random walk is finished
//                i.e., when # of steps taken == max. # of steps     
{
    return mySteps == myMaxSteps;
}

void RandomWalk::Next()
// postcondition: next step in random walk simulated     
{
    TakeStep();
}

void RandomWalk::Display()
// postcondition: current status of walk displayed     
{
    cout << "pos = " << myPosition << "\t";
    cout << "steps = " << mySteps << endl;
}

int RandomWalk::GetPosition()
// postcondition: returns position of "frog" (x coordinate)
{
    return myPosition;
}

int RandomWalk::GetSteps()
// postcondition: returns number of steps taken by "frog"     
{
    return mySteps;
}


int main()
{
    int numSteps;
    cout << "enter # of steps: ";
    cin >> numSteps;

    RandomWalk frog(numSteps);

    for(frog.First(); ! frog.IsDone(); frog.Next())
    {
        frog.Display();
    }
    cout << "final position = " << frog.GetPosition() << endl;
    return 0;
}