cannot convert parameter 1 from 'PrintVisitor *const ' to 'Visirot &' - c++

Question

I used two design pattern Composite and Visitor. I have no problem with Composite.But when he began writing derived classes for input and output got some errors, solution which I did never found. Although in reality, and if everything is InputVisitor done so remained only PrintVisitor and main().
Here is my code:
UPD: I rewrite some parts of code. Now I have no erros, but it only open terminal and nothind doing...
P.S. Maybe I did not properly implement of patterns. Someone has a better idea?
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;
class BaseComponent {
public:
virtual void add(BaseComponent *)=0;
virtual void accept(class Visitor &)=0;
};
class Card :public BaseComponent {
public:
Card (string bookName, vector<string> authors, int year): _bookName(bookName), _authors(authors), _year(year) {}
string getBookName() const {
return _bookName;
}
vector<string> getAuthors() const {
return _authors;
}
int getYear() const {
return _year;
}
void setBookName(string bookName) {
_bookName = bookName;
}
void setAuthors(vector<string> authors) {
copy(authors.begin(), authors.end(), _authors.begin());
}
void setYear(int year) {
_year = year;
}
void add(BaseComponent *){}
void accept(class Visitor &);
private:
string _bookName;
vector<string> _authors;
int _year;
};
class Folder :public BaseComponent {
public:
Folder(): _folderName(""), _parentFolder("") {}
Folder(string parentFolder): _folderName(""), _parentFolder(parentFolder) {}
string getFolderName() const {
return _folderName;
}
string getParentName() const {
return _parentFolder;
}
vector<BaseComponent*> getSubFolders() const {
return _subFolders;
}
void setFolderName(string folderName) {
_folderName = folderName;
}
void setParentFolder(string parentFolder) {
_parentFolder = parentFolder;
}
void add(BaseComponent *component) {
_subFolders.push_back(component);
}
void accept(class Visitor &);
private:
string _folderName;
string _parentFolder;
vector<BaseComponent*> _subFolders;
};
class Visitor {
public:
virtual void visitCard(Card *)=0;
virtual void visitFolder(Folder *)=0;
};
void Card::accept(class Visitor &visitor) {
visitor.visitCard(this);
}
void Folder::accept(class Visitor &visitor) {
visitor.visitFolder(this);
}
class InputVisitor :public Visitor {
public:
InputVisitor(string file): _file(file){}
void setFile(string file) {
_file = file;
}
void visitCard(Card *){}
void visitFolder(Folder *folder){
ifstream input(_file);
string folderName;
getline(input, folderName);
folder->setFolderName(folderName);
string fileName;
while (!input.eof()) {
input >> fileName;
if (fileName == "----") {
break;
} else {
Folder *subFolder = new Folder(folderName);
InputVisitor *inputVisitor = new InputVisitor(fileName);
subFolder->accept(*inputVisitor);
folder->add(subFolder);
}
}
while (!input.eof()) {
string name, tempAuthor;
vector<string> authors;
int n, year;
input >> name;
input >> n;
for (int i = 0; i<n; ++i) {
input >> tempAuthor;
authors.push_back(tempAuthor);
}
input >> year;
Card *subBook = new Card(name, authors, year);
folder->add(subBook);
}
input.close();
}
private:
string _file;
};
class PrintVisitor :public Visitor {
public:
PrintVisitor(string outputFile): _outputFile(outputFile) {}
void setOutputFile(string outputFile) {
_outputFile = outputFile;
}
void visitFolder(Folder *folder) {
ofstream output(_outputFile);
output << folder->getFolderName() << endl << "\t";
vector<BaseComponent*> subFolders = folder->getSubFolders();
vector<BaseComponent*>::iterator it;
for (it=subFolders.begin(); it!=subFolders.end(); ++it) {
(*it)->accept(*this);
}
output.close();
}
void visitCard(Card *card) {
ofstream output(_outputFile);
output << "Book: " << card->getBookName() << endl
<< "Author(s): ";
vector<string> authors = card->getAuthors();
for (vector<string>::iterator it=authors.begin(); it!=authors.end(); ++it) {
output << *it << " ";
}
output << endl << "Year: " << card->getYear();
output.close();
}
private:
string _outputFile;
};
int main() {
Folder root;
root.accept(*(new InputVisitor("root.txt")));
root.accept(*(new PrintVisitor("output.txt")));
return 0;
}

Answer 1

In this code:
InputVisitor *input;
input->setFile("root.txt");
root->accept(input); //Here
InputVisitor is a *input. Your accept function takes a reference to a visitor. Change it to:
root->accept(*input); //Here
and all will be fine, aside from the typo I mentioned in the comment.
If you remove all the class in front of names for classes, the compiler will tell you when there is a misspelled class name. Otherwise, it will just treat it as "there'll be a class named Visirot at some point in the future, and I don't really care what's in it right now.

Answer 2

Here is the declaration of BaseComponent::accept:
virtual void accept(class Visirot &)=0;
Here is the call:
root->accept(input); //Here
Here is the declaration of input:
InputVisitor *input;
So, first, the declaration of BaseComponent::accept apparently has a typo; Visirot should probably be Visitor.
Second, accept takes a Visitor&, but it's being called with an InputVisitor*. InputVisitor is derived from Visitor, soInputVisitor*is convertible toVisitor*andInputVisitor&is convertible toVisitor&, but there is no conversion from a pointer-to-type into a reference-to-type. So either changeBaseComponent::accept` to take a pointer or change the call to pass a reference.

Answer 3

First problem.
Assuming the typo Visirot is fixed, then at line 152 you have
subFolders[i]->accept(this); //Here some probrem
which passes a pointer to T where a T is expected.
Just dereference that pointer:
subFolders[i]->accept(*this);
Second problem.
Applying the same fixes in the main program would be wrong:
int main() {
BaseComponent *root;
InputVisitor *input;
input->setFile("root.txt");
root->accept(*input); //Here
PrintVisitor *output;
output->setOutputFile("output.txt");
root->accept(output); //And here
return 0;
}
This dereferences uninitialized pointers, which yields Undefined Behavior.
Don't do that.
Rewrite it as e.g.
int main() {
Folder root;
InputVisitor input;
input.setFile("root.txt");
root.accept(input); //Here
PrintVisitor output;
output.setOutputFile("output.txt");
root.accept(output); //And here
}
(and possibly replace Folder with whatever concrete class you want there.)
Third problem.
At line 144 you're assigning to a stream:
_outputFile = ofstream(outputFile);
where _outputFile is a member of type ofstream, and outputFile is a string.
This uses a C++11 feature (rvalue assignment of streams) that g++ didn't implement as of version 4.7.1.
Presumably the idea is to close _outputFile and reopen it: just do that, and the code will be much more portable:
// Add failure checking:
_outputFile.close();
_outputFile.open( outputFile );
Also, more descriptive naming would be good…
General problem set in the given code.
Compiling the above yields a number of warnings about signed/unsigned comparisons and unused local variables. Fix all that. Build at highest practical warning level, -Wall with g++ and /W4 with Visual C++, and make it compile cleanly.
Logic errors & testing.
Even when it compiles cleanly, there can and usually will remain logic errors. To root out those, devise a set of exactly reproducible tests, complete with any necessary test data.