I know this question has been asked before but please hummer me. I am having trouble getting a grasp on how to initialize a class.
Here is the code in question.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
//------------------------------------------------------------------- ---------------------------
class Date //Class Date
{
public:
int day;
int month;
int year;
Date();
Date(int,int,int);
~Date(void);
};
Date::Date(void)
{
day = 0;
month = 0;
year = 0;
}
Date::Date(int month, int day, int year)
{
day = day;
month = month;
year = year;
} //Class Date
//---------------------------------------------------------------------------------------------
//Class Book
class Book
{
public:
string _title;
string _author;
Date _published;
string _publisher;
float _price;
string _isbn;
int _page;
int _copies;
Book();
Book(string,string,Date,string,float,string,int,int);
~Book(void);
};
Book::Book(void)
{
_title = "";
_author = "";
//_published;
_publisher = "";
_price = 0;
_isbn = "";
_page = 0;
_copies = 0;
}
Book::Book(string title, string author, Date published, string publisher, float price, string isbn, int page, int copies)
{
_title = title;
_author = author;
_published = published;
_publisher = publisher;
_price = price;
_isbn = isbn;
_page = page;
_copies = copies;
} //Class Book
//---------------------------------------------------------------------------------------------
class Node //Class Node
{
friend class LinkedList;
private:
Book *_book;
Node *_next;
public:
Node(void);
Node(Book*);
Node(Book*,Node*);
~Node(void);
};
Node::Node(void)
{
_book = NULL;
_next = NULL;
}
Node::Node(Book *book)
{
_book = book;
_next = NULL;
}
Node::Node(Book *book, Node *next)
{
_book = book;
_next = next;
} //Class Node
//---------------------------------------------------------------------------------------------
class LinkedList //Class LinkedList
{
private:
Node *_head;
Node *_tail;
public:
LinkedList(void);
LinkedList(Book*);
~LinkedList(void);
void insert_front(Book*);
void insert_rear(Book*);
void print_list(void);
};
LinkedList::LinkedList(void)
{
_head = NULL;
_tail = NULL;
}
LinkedList::LinkedList(Book *book)
{
_head = new Node(book);
_tail = _head;
} //Class LinkedList
//---------------------------------------------------------------------------------------------
void LinkedList::insert_front(Book *book)
{
if(_head == NULL)
{
_head = new Node(book);
_tail = _head;
}
else
_head = new Node(book, _head);
}
void LinkedList::insert_rear(Book *book)
{
if(_head == NULL)
{
_head = new Node(book);
_tail = _head;
}
else
{
_tail -> _next = new Node(book);
_tail = _tail -> _next;
}
}
void LinkedList::print_list(void)
{
Node *temp = _head;
while(temp!= NULL)
{
cout << temp -> _book -> _title << endl;
cout << temp -> _book -> _author << endl;
cout << temp -> _book -> _publisher << endl;
temp = temp -> _next;
cout << endl;
}
}
LinkedList::~LinkedList(void)
{
}
//---------------------------------------------------------------------------------------------
//Main
int main(void)
{
LinkedList myList;
ifstream myFile("input.txt");
string title;
string author;
Date published; // was "Date published(int,int,int);"
string publisher;
float price;
string isbn;
int page;
int copies;
while(myFile)
{
getline(myFile,title);
getline(myFile,author);
//getline(myFile,published);
getline(myFile,publisher);
//getline(myFile,price);
getline(myFile,isbn);
//getline(myFile,page);
//getline(myFile,copies);
myList.insert_front(new Book(title,author,published,publisher,price,isbn,page,copies));
}
myList.print_list();
return 0;
}
There error I am interested in is:
assignment3.cpp:213:33: error: no matching constructor for initialization of 'Book' ...Book(title,author,published,publisher,price,isbn,page,copies)); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ assignment3.cpp:67:7: note: candidate constructor not viable: no known conversion from 'Date (int, int, int)' to 'Date' for 3rd argument Book::Book(string title, string author, Date published, string publis... ^ assignment3.cpp:38:7: note: candidate constructor (the implicit copy constructor) not viable: requires 1 argument, but 8 were provided class Book ^ assignment3.cpp:54:7: note: candidate constructor not viable: requires 0 arguments, but 8 were provided Book::Book(void) ^ 1 error generated.
I made the change suggested and now I get a different error:
Undefined symbols for architecture x86_64: "Date::~Date()", referenced from: Book::Book() in assignment3-0f3b1c.o Book::Book(std::__1::basic_string, std::__1::allocator >, std::__1::basic_string, std::__1::allocator >, Date, std::__1::basic_string, std::__1::allocator >, float, std::__1::basic_string, std::__1::allocator >, int, int) in assignment3-0f3b1c.o _main in assignment3-0f3b1c.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
Date
class. Where is it? Same issue withBook
class andNode
class. If you declare destructors, you also have to define them. – AnTDate
class does not need user-defined copy constructor - it does not manage any non-shallow resources. Just because something is passed by value does not mean it needs a user-defined copy constructor. Quite the opposite, the primary purpose of Rule of Three is actually to encourage designs that work properly with compiler-provided copy semantics. In this case compiler-provided copying is perfectly sufficient forDate
class, no need to do anything. – AnTLinkedList
class. And now you are asking how to define destructors? – AnT