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#include <iostream>
#include <string>
#include <memory>
#include <vector>
#include <list>
#include <cstdlib>
#include <ctime>
class FoodHistory {
public:
int numMeals = 0; // plus many other data members
};
class Animal {
public:
int i = 0;
double d = 0;
FoodHistory* foodHistory = new FoodHistory();
public:
class Memento {
private:
std::unique_ptr<Animal> copy;
public:
Memento(): copy (nullptr) {}
Memento (const Animal* being): copy (being->clone()) {}
friend class Animal;
};
virtual ~Animal() noexcept = default;
Animal& operator = (const Animal& other) {
if (&other == this) return *this;
i = other.i; d = other.d; foodHistory = other.foodHistory;
*foodHistory = *other.foodHistory; // Attempt at debugging fails
return *this;
}
virtual void change() = 0;
virtual void display() const = 0;
virtual Memento createMemento() const {return Memento (this);}
virtual Animal& restoreMemento (const Memento& memento) {return assign (*memento.copy);}
private:
virtual std::unique_ptr<Animal> clone() const = 0;
virtual Animal& assign (const Animal&) = 0 ;
};
template <typename DERIVED>
class AnimalCRTP: public Animal {
protected:
virtual std::unique_ptr<Animal> clone() const override {
return std::unique_ptr<Animal>(new DERIVED (static_cast<const DERIVED&>(*this)));
}
virtual Animal& assign (const Animal& being) override { // return Animal& because may throw std::bad_cast
return static_cast<DERIVED&>(*this) = dynamic_cast<const DERIVED&>(being);
}
};
class Dog: public AnimalCRTP<Dog> {
public:
virtual void change() override {i++; d += (float)(std::rand() % 10) / 10; foodHistory->numMeals++;}
virtual void display() const override {std::cout << "Dog {" << i << ", " << d << "}, foodHistory->numMeals = " << foodHistory->numMeals<< std::endl;}
};
class Cat: public AnimalCRTP<Cat> {
public:
virtual void change() override {i += 10; d += (float)(std::rand() % 10) / 10; foodHistory->numMeals++;}
virtual void display() const override {std::cout << "Cat {" << i << ", " << d << "}, foodHistory->numMeals = " << foodHistory->numMeals<< std::endl;}
};
class Command { // The rest of the code is just for running the programming
private:
typedef void (Animal::*Action)();
std::vector<Animal*> receivers;
// std::vector<FoodHistory*> foodHistories; // these need their own Mementos perhaps???
Action action;
static int numReceivers;
static std::vector<std::vector<Command*>> commandList;
static std::vector<std::vector<Animal::Memento>> mementoList;
static std::size_t numCommands;
static std::size_t maxCommands;
public:
Command (const std::vector<Animal*>& newReceivers, Action newAction): receivers (newReceivers), action (newAction) {
numReceivers = receivers.size();
}
virtual void execute() {
if (mementoList.size() < numCommands + 1)
{
mementoList.resize (numCommands + 1);
mementoList[numCommands].resize (numReceivers);
}
for (int i = 0; i < numReceivers; ++i)
mementoList[numCommands][i] = receivers[i]->createMemento();
if (commandList.size() < numCommands + 1)
{
commandList.resize (numCommands + 1);
commandList[numCommands].resize (numReceivers);
}
for (int i = 0; i < numReceivers; ++i)
commandList[numCommands][i] = this;
if (numCommands > maxCommands)
maxCommands = numCommands;
numCommands++;
for (Animal* x: receivers)
(x->*action)();
if (mementoList.size() < numCommands + 1)
{
mementoList.resize (numCommands + 1);
mementoList[numCommands].resize (numReceivers);
}
if (commandList.size() < numCommands + 1)
{
commandList.resize (numCommands + 1);
commandList[numCommands].resize (numReceivers);
}
for (int i = 0; i < numReceivers; ++i)
{
mementoList[numCommands][i] = receivers[i]->createMemento();
commandList[numCommands][i] = this;
}
}
static void undo() {
if (numCommands == 0)
{
std::cout << std::endl << "[There is nothing to undo at this point.]" << std::endl << std::endl;
return;
}
for (int i = 0; i < numReceivers; ++i)
commandList[numCommands - 1][i]->receivers[i]->restoreMemento (mementoList[numCommands - 1][i]);
numCommands--;
}
void static redo() {
if (numCommands > maxCommands)
{
std::cout << std::endl << "[There is nothing to redo at this point.]" << std::endl << std::endl;
return ;
}
for (int i = 0; i < numReceivers; ++i)
commandList[numCommands + 1][i]->receivers[i]->restoreMemento (mementoList[numCommands + 1][i]);
numCommands++;
}
};
int Command::numReceivers;
std::vector<std::vector<Command*>> Command::commandList;
std::vector<std::vector<Animal::Memento>> Command::mementoList;
std::size_t Command::numCommands = 0;
std::size_t Command::maxCommands = 0;
int main() {
srand (std::time (nullptr));
int i;
std::vector<Animal*> pets = {new Dog, new Cat};
Command *commands[2];
commands[1] = new Command (pets, &Animal::change); // add whatever other types of commands from Animal functions
for (const Animal* x: pets)
x->display();
std::cout << std::endl << "0.Exit, 1.Change, 2.Undo, 3.Redo: ";
std::cin >> i;
while (i != 0)
{
if (i < 0 || i > 3)
{
std::cout << "Enter a proper choice: ";
std::cin >> i;
continue;
}
else if (i == 2)
Command::undo();
else if (i == 3)
Command::redo();
else
commands[i]->execute();
for (const Animal* x: pets)
x->display();
std::cout << std::endl << "0.Exit, 1.Change, 2.Undo, 3.Redo: ";
std::cin >> i;
}
}
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