2. Recipes

#include <iostream>
#include <cstring>

using namespace std;

class Recipe
{
    int number;
    char name[100];
    char* contents;
public:
    Recipe()                                //Default constructor
    {
        contents=new char[0];
    }
    Recipe(int n, char* na, char* c)        //Constructor with parameters set
    {
        number = n;
        contents = new char [strlen(c)+1];  //Allocating enough memory to copy the contents, +1 in order to make place for '\0'
        strcpy(name,na);
        strcpy(contents,c);
    }

    Recipe &operator++()                    //prefix operator. Incrementing and returning
    {
        ++number;
        return *this;
    }

    Recipe operator++(int)                  //postfix operator. Returning non-incremented value
    {
        Recipe temp(number,name,contents);  //Remembering the current value
        ++(*this);                          //using prefix operator on the current value
        return temp;                        //Returning the value we remembered
    }

    friend ostream &operator<<(ostream &output, const Recipe &rhs)  //Output operator
    {
        output<<rhs.number<<endl<<rhs.name<<endl<<rhs.contents<<endl;
        return output;
    }

    Recipe &operator=(const Recipe &rhs)    //Operator=, you just need to copy everything from rhs to this.
    {
        this->number=rhs.number;
        delete[] contents;
        this->contents = new char[strlen(rhs.contents)+1];
        strcpy(this->name,rhs.name);
        strcpy(this->contents,rhs.contents);
        return *this;
    }

    bool operator==(const Recipe &rhs)  //We need to compare if two recipes are equal
    {
        return !strcmp(this->name,rhs.name);    //strcmp will be 0 if strings are equal. Since we want 1 if strings are equal, we negate it
    }

    bool operator>(const Recipe &rhs)   //Comparing two recipes by ingredients (needed for newBook)
    {
        return this->number>rhs.number;
    }

    void set_num_ing(int n)
    {
        number=n;
    }

    void set_name(char *n)
    {
        strcpy(name,n);
    }

    void set_contents(char *c)
    {
        delete[] contents;
        contents = new char[strlen(c)+1];
        strcpy(contents,c);
    }

    ~Recipe()               //Destructor
    {
        delete[] contents;
    }
};

class RecipesBook
{
    char name[100];
    Recipe* recipes;
    int number;
public:
    RecipesBook()              //Default constructor
    {
        recipes=new Recipe[0];
    }
    RecipesBook(char *n)    //Constructor that only takes name as argument
    {
        recipes=new Recipe[0];
        strcpy(name,n);
        number=0;           //We will use this later to know if we should call delete or not
    }

    RecipesBook &operator+=(const Recipe &rhs)  //Operator used to add a recipe to the book if it's not present
    {
        bool isPresent=false;                   //This will be true if the recipe is already present in the book
        for(int i=0;i<number;i++)               //For all recipes i from 0 to number in the book
            if(recipes[i]==rhs)                 //If there's an equal recipe, then isPresent is true
                isPresent=true;

        if(isPresent)                           //If the recipe is already in, we don't have to add anything and can return
            return *this;

        Recipe* temp = new Recipe[number];      //A temporary array of recipes
        for(int i=0;i<number;i++)               //We copy all recipes from our current array to the temp array
            temp[i]=recipes[i];

        delete[] recipes;

        recipes = new Recipe[number+1];         //Making the array we deleted again, but this time it can hold 1 more recipe (so we can add a new one)

        for(int i=0;i<number;i++)               //Copying all the recipes from temp back into our book
            recipes[i]=temp[i];

        recipes[number]=rhs;                    //Adding the last one at the end of the book
        number++;                               //We increase the recipe counter

        return *this;                           //Return the result
    }

    friend ostream &operator<<(ostream &output, RecipesBook &rhs)   //Operator to print the book
    {
        output<<rhs.name<<endl;                         //First we print the name of the book
        for(int i=0;i<rhs.number;i++)                   //Then we print all recipes
            output<<rhs.recipes[i]<<endl;
        return output;
    }

    RecipesBook novaBrosura(Recipe &r)                      //The newBook function
    {
        RecipesBook result(this->name);                 //We create a new book with the name of the original one
        for(int i=0;i<this->number;i++)                 //We check all recipes in the original
            if(r>this->recipes[i])                      //If recipe r has more ingredients than it recipe i
                result+=recipes[i];                     //Add recipe i to the new book
        for(int i=0;i<result.number;i++)                //We also need to increment all recipes by 1
            result.recipes[i]++;
        return result;
    }

    RecipesBook(const RecipesBook &rhs)
    {
        this->number=rhs.number;                        //We copy the number
        this->recipes=new Recipe[this->number];             //Allocate memory for recipes
        strcpy(this->name,rhs.name);                    //Copy the name
        for(int i=0;i<rhs.number;i++)                   //We copy all recipes one by one
            this->recipes[i]=rhs.recipes[i];
    }

    ~RecipesBook()      //Destructor
    {
        delete[] recipes;
    }
};

int main()
{
    Recipe rec;
    int n;
    char name[100], contents[200];
    int num_ing;
    cin >> name >> n;
    RecipesBook b1(name);
    Recipe last;
    for(int i = 0; i < n; i++){
        cin >> num_ing >> name >> contents;
        Recipe r(num_ing, name, contents);
        b1 += r;
        last = r;
    }
    cout << b1;
    cin >> num_ing >> name >> contents;
    rec.set_num_ing(num_ing);
    rec.set_name(name);
    rec.set_contents(contents);
    b1+=rec;
    cout << b1;
    RecipesBook b2 = b1.novaBrosura(rec);
    cout << b2;
    // testing copy constructor
    cout << "b2 copy" << endl;
    RecipesBook rb = b2;
    last.set_name("changed-name");
    rb += last;
    cout << rb;
    cout << "original" << endl;
    cout << b2;
    return 0;
}