walk.cpp

C++&datastructure书籍源码,以前外教提供现在与大家共享

#include "walk.h"
#include "dice.h"

RandomWalk::RandomWalk(int maxSteps)  
  : myPosition(0),
    mySteps(0),
    myMaxSteps(maxSteps)
// postcondition: no walk has been taken, but walk is ready to go    
{
    // work done in initializer list
}

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

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

bool RandomWalk::HasMore()
// postcondition: returns true when random walk still going
//                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::Simulate()
// postcondition: one simulation completed     
{
    for(Init(); HasMore(); Next())
    {
	// simulation complete using iterator methods
    }
}

int RandomWalk::Position() const
// postcondition: returns position of walker (x coordinate)
{
    return myPosition;
}

int RandomWalk::Current() const
// postcondition: retrns position of walker (x coordinate)
{
    return Position();
}

int RandomWalk::TotalSteps() const
// postcondition: returns number of steps taken by walker     
{
    return mySteps;
}