weird typing mismatch c++ - c++

Question

So I am not sure why I am getting this error when in the .h files it was defined that format was a Parser*. The compiler tells me that in the method Parser::changeformat(int) I cannot convert an int* to a Parser* pointer(the cpp files aren't done yet so please ignore all the other methods if they throw errors or look weird). Why is this happening and how can I fix it. This may have something to do with inheritance so I'll point out a subclass of parser that would fit. Also, in any case if you have suggestions about other parts then be my guest.
Parser.h
#ifndef PARSER_H_
#define PARSER_H_
#include <string>
#include <iostream>
#include <fstream>
/*
* This is a parser for reading and writing files
* it takes in an integer for the file type it should read
* or none if you would like to change it later and reuse
* the parser
*/
class Parser {
public:
Parser();
Parser(int);
virtual ~Parser();
void open();
bool open(std::string&);
bool read();
bool write();
bool close();
void changeformat(int);
private:
int filetype = -1;
Parser* format = 0;
};
#endif /* PARSER_H_ */
Parser.cpp
#include "Parser.h"
Parser::Parser()
{
filetype = -1;
}
Parser::Parser(int filetype)
{
switch(filetype)
{
case 0:
{
//load xml format via instantiating xmlpar subclass and overloading methods
break;
}
case 1:
{
//load txt format
break;
}
}
}
Parser::~Parser()
{
if(this->format)
delete this->format;// TODO Auto-generated destructor stub
}
//the classes below are to be overloaded with a subclass's own method
void Parser::open()
{
return;
}
bool Parser::open(std::string& filename)
{
if(this->format->open(filename))
{
std::cout<<"OK: "+filename+" opened\n";
return true;
}
else
{
std::cout<<"Error: "+filename+" unable to be opened\n";
return false;
}
}
bool Parser::read()
{
//make failure checks for all past open in this cpp
return this->format->read();
}
bool Parser::write()
{
return this->format->write();
}
bool Parser::close()
{
return this->format->close();
}
void Parser::changeformat(int)
{
switch(filetype)
{
case -1:
break;
case 0:
{
this->format = new xmlpar();
break;
}
case 1:
{
//load txt format
break;
}
}
}
xmlpar.h
/*
* xmlpar.h
*
* Created on: Jul 22, 2015
* Author: root
*/
#ifndef XMLPAR_H_
#define XMLPAR_H_
#include "Parser.h"
#include <fstream>
#include <string>
class xmlpar: public Parser{
public:
xmlpar();
virtual ~xmlpar();
bool open(std::string&);//opens a stream and checks association
bool read(std::fstream&);//creats dom tree and hands it forward via reference
bool write(std::fstream&);//edits domtree but does not write to the physical file
bool close(std::fstream&);//the dom tree is flushed, the fstream associated to the file is closed and everyone is happy... I think
private:
std::fstream *file= 0;
bool flush();//write dom tree in memory to physical file
};
#endif /* XMLPAR_H_ */
xmlpar.cpp
/*
* xmlpar.cpp
*
* Created on: Jul 22, 2015
* Author: root
*/
#include "xmlpar.h"
xmlpar::xmlpar()
{
}
bool xmlpar::open(std::string& filename)
{
file = new std::fstream(filename, std::ios::in|std::ios::out);
return file->good();
}
bool xmlpar::close(std::fstream &file)
{
this->write(file);
file->close();
//write failcheck here
}
xmlpar::~xmlpar() {
this->close(file);
}

Answer 1

You are trying to instantiate an instance of xmlpar that is derived from Parser base class without including headers of derived class xmlpar at Parser.cpp. The compiler is not finding definition for xmlpar here:
this->format = new xmlpar();
I also doubt this is a good practice.