Part 1

Go through the following sections of the class zyBook, doing the Participation Activities and Challenge Activities. We will be looking at whether you have ever successfully completed them; it does not matter how many attempts you make before a successful completion (or how many attempts you make after a successful completion if you want to experiment).

• 9.1 and 9.6

Project 7 Warmup: Virtual Pets

To help ease you into the world of classes you'll need for Project 7, we've designed these warmup exercises. (You will not turn in any of the code you write because of these warmups.)

Did you ever have a Tamagotchi or Gigapet when you were young (during one of the toy's revivals since its inception many years ago), the virtual pet that you had to "feed" and care for to keep it alive? Here's your chance to implement a very simple one. This program compiles and runs, but does not produce the output it should, because the implementations of the member functions are incomplete or incorrect. Fix them so that the program produces the desired output.

The places to make a change are denoted by TODO comments. You must make no changes whatsoever to the reportStatus, careFor, or main functions.

After you get everything working, try the each of the following independent experiments to test your understanding of some of concepts:

1. Try declaring the health member function private instead of public, and make sure you understand the resulting compilation error.
2. Comment out the entire implementation of Pet::eat, all the way from the void Pet::eat(int amt) to its close curly brace. Make sure you understand the resulting build error.
3. In main, try replacing myPets[0] = new Pet("Fluffy", 2); with myPets[0] = new Pet("Fluffy"); or myPets[0] = new Pet;, and make sure you understand the resulting compilation error.
4. Try removing the const from the implementation, but not the declaration of the isAlive member function. Notice the compilation error.
5. Try removing the const from both the declaration and the implementation of the isAlive member function. Make sure you understand why the use of that function doesn't compile in reportStatus, but does compile in careFor and main.

The program

Here is the incomplete program. It will build successfully, but when run will not produce the desired output.

#include <iostream>
#include <string>

using namespace std;

class Pet
{
  public:
    Pet(string nm, int initialHealth);
    void eat(int amt);
    void play();
    string name() const;
    int health() const;
    bool isAlive() const;
  private:
    string m_name;
    int m_health;
};

  // Initialize the state of the pet
Pet::Pet(string nm, int initialHealth)
{
    m_name = nm;
    m_health = initialHealth;
}

void Pet::eat(int amt)
{
      // TODO: Increase the pet's health by the amount
}

void Pet::play()
{
      // TODO: Decrease the pet's health by 1 for the energy consumed
}

string Pet::name() const
{
      // TODO: Return the pet's name.  Delete the following line and
      // replace it with the correct code.
    return ""; // This implementation compiles, but is incorrect
}

int Pet::health() const
{
      // TODO: Return the pet's current health level.  Delete the
      // following line and replace it with the correct code.
    return 99; // This implementation compiles, but is incorrect
}

bool Pet::isAlive() const
{
      // TODO: Return whether pet is alive.  (A pet is alive if
      // its health is greater than zero.)  Delete the following
      // line and replace it with the correct code.
    return true; // This implementation compiles, but is incorrect
}

/////////
// Do not change any code below this point
/////////

void reportStatus(const Pet* p)
{
    cout << p->name() << " has health level " << p->health();
    if ( ! p->isAlive())
        cout << ", so has died";
    cout << endl;
}

void careFor(Pet* p, int d)
{
    if ( ! p->isAlive())
    {
        cout << p->name() << " is still dead" << endl;
        return;
    }

      // Every third day, you forget to feed your pet
    if (d % 3 == 0)
        cout << "You forgot to feed " << p->name() << endl;
    else
    {
        p->eat(1);  // Feed the pet one unit of food
        cout << "You fed " << p->name() << endl;
    }

    p->play();
    reportStatus(p);
}

int main()
{
    Pet* myPets[2];
    myPets[0] = new Pet("Fluffy", 2);
    myPets[1] = new Pet("Frisky", 4);
    for (int day = 1; day <= 9; day++)
    {
        cout << "======= Day " << day << endl;
        for (int k = 0; k < 2; k++)
            careFor(myPets[k], day);
    }
    cout << "=======" << endl;
    for (int k = 0; k < 2; k++)
    {
        if (myPets[k]->isAlive())
            cout << "Animal Control officers have come to rescue "
                 << myPets[k]->name() << endl;
        delete myPets[k];
    }
}

The desired output

Here is the output we would like the program to produce:

======= Day 1
You fed Fluffy
Fluffy has health level 2
You fed Frisky
Frisky has health level 4
======= Day 2
You fed Fluffy
Fluffy has health level 2
You fed Frisky
Frisky has health level 4
======= Day 3
You forgot to feed Fluffy
Fluffy has health level 1
You forgot to feed Frisky
Frisky has health level 3
======= Day 4
You fed Fluffy
Fluffy has health level 1
You fed Frisky
Frisky has health level 3
======= Day 5
You fed Fluffy
Fluffy has health level 1
You fed Frisky
Frisky has health level 3
======= Day 6
You forgot to feed Fluffy
Fluffy has health level 0, so has died
You forgot to feed Frisky
Frisky has health level 2
======= Day 7
Fluffy is still dead
You fed Frisky
Frisky has health level 2
======= Day 8
Fluffy is still dead
You fed Frisky
Frisky has health level 2
======= Day 9
Fluffy is still dead
You forgot to feed Frisky
Frisky has health level 1
=======
Animal Control officers have come to rescue Frisky