Help with classes

[rxfeliciano]

I am getting a long error when I try and compile my multiset.cpp file. Something about the vector I am using. Error looks as follows:

In file included from /usr/lib/gcc/x86_64-pc-cygwin/4.8.2/include/c++/vector:62:0,
from multiset.h:5,
from multiset.cpp:1:
/usr/lib/gcc/x86_64-pc-cygwin/4.8.2/include/c++/bits/stl_construct.h: In instantiation of ‘void std::_Construct(_T1*, _Args&& ...) [with _T1 = Item; _Args = {}]’:
/usr/lib/gcc/x86_64-pc-cygwin/4.8.2/include/c++/bits/stl_uninitialized.h:495:43: required from ‘static void std::__uninitialized_default_n_1<_TrivialValueType>::__uninit_default_n(_ForwardIterator, _Size) [with _ForwardIterator = Item*; _Size = long unsigned int; bool _TrivialValueType = false]’
/usr/lib/gcc/x86_64-pc-cygwin/4.8.2/include/c++/bits/stl_uninitialized.h:544:33: required from ‘void std::__uninitialized_default_n(_ForwardIterator, _Size) [with _ForwardIterator = Item*; _Size = long unsigned int]’

//multiset.h file

  #ifndef MULTISET_H_
#define MULTISET_H_

#include "item.h"
#include <vector>


using namespace std;


class Multiset{
	Multiset();
	private:
		 vector<Item> items;

	public:
		void add_item(string name, int quantity);
		void remove_item(string name);

		
};
#endif

//multiset.cpp file
#include "multiset.h"
#include <vector>

using namespace std;

Multiset::Multiset(){
	items.resize(0);
}
void Multiset::add_item(string name, int quantity){
	items.push_back(Item(name, quantity));
}
void Multiset::remove_item(string name){
	for(int i = 0; i< items.size(); i++){
		if( name == items[i].get_name()){
			items.erase(items.begin());
		}
	}
}

[helios]

Post the definition of Item.

[rxfeliciano]

Here it is. Thanks for any help.

//item.h
#ifndef ITEM_H_
#define ITEM_H_

class Item{
	//Item(string name, int quantity);

	private:
		std::string name;
		int quantity;
	
	public:
		Item(std::string name, int quantity);
		std::string get_name();
		int get_quantity();
};
#endif

//item.cpp
#include <vector>
#include <string>
#include "item.h"

Item::Item(std::string name, int quantity){
	this->name = name;
	this->quantity = quantity;
}
std::string Item::get_name(){
	return name;
}
int Item::get_quantity(){
	return quantity;
}

[rxfeliciano]

I have been messing around with the code a bit after doing some reading so the multiset files have changed as well but I still get same error. I think it is an include problem.

#ifndef MULTISET_H_
#define MULTISET_H_

#include "item.h"

class Multiset{
	Multiset();
	private:
		std::vector<Item> items;

	public:
		void add_item(std::string name, int quantity);
		void remove_item(std::string name);

		
};
#endif

#include <vector>
#include <string>
#include "multiset.h"


using namespace std;

Multiset::Multiset(){
	items.resize(0);
}
void Multiset::add_item(string name, int quantity){
	items.push_back(Item(name, quantity));
}
void Multiset::remove_item(string name){
	for(int i = 0; i< items.size(); i++){
		if( name == items[i].get_name()){
			items.erase(items.begin());
		}
	}
}

[helios]

std::vector<T> needs T to have a default constructor. Your definition of Item::Item(std::string, int) causes the compiler to not generate one automatically, you'll have to define one yourself. Something like simply Item(){} will work.

[cire]

You need to #include <string> in Item.h, although I don't know if that's your only problem.