class item
{
string name;
string identifier;
public:
  item( string name,string id):{this->name=name;this->identifier=id;}
        friend ostream& operator<<(ostream&, const item&);
        friend istream& operator>>(istream&, item&);
};
ostream& operator<<(ostream& out, const item& temp)
{
	out<<item.name<<" "<<item.identifier<<endl;
	return out;
}
istream& operator>>(istream& in, Cmessage& temp)
{
	getline(in,item.name);//in case sring has space char
	getline(in,item.identifier);

	return in;
}
class CGuser
{
	bool online;
	int score;
	string name;
	string password;
	string IP;
	vector<item> messages;
	vector<string> v_friends;
	vector<string> groups;
public:
        CGuser(string name, string password)	
       {	
        this->name=name;
        this->password=password;
        this->score=0;}
	friend ostream& operator<<(ostream&, const CGuser&);
	friend istream& operator>>(istream&, CGuser&);

ostream& operator<<(ostream& out, const CGuser& temp)
{
	int size;
	out<<temp.online<<endl;
	out<<temp.score<<endl;
	out<<temp.name<<endl;
	out<<temp.password<<endl;
	out<<temp.IP<<endl;

	size=temp.messages.size();
	out<<size<<" ";
	for(int i=0;i<size;i++)
		out<<temp.messages[i]<<endl;

	size=temp.v_friends.size();
	out<<size<<" ";
	for(int i=0;i<size;i++)
		out<<temp.v_friends[i]<<endl;

	size=temp.groups.size();
	out<<size<<" ";
	for(int i=0;i<size;i++)
		out<<temp.groups[i]<<endl;

	out<<endl;
	return out;
}
istream& operator>>(istream& in, CGuser& temp)
{
	int size;
	string stmp;
	Cmessage cmg;

	in>>temp.online;
	in>>temp.score;
	getline(in,temp.name);
	getline(in,temp.password);
	getline(in,temp.IP);

	in>>size;
	for(int i=0;i<size;i++)
	{
		in>>cmg;
		temp.messages.push_back(cmg);
	}

	in>>size;
	for(int i=0;i<size;i++)
	{
		getline(in,stmp);
		temp.v_friends.push_back(stmp);
	}
	
	in>>size;
	for(int i=0;i<size;i++)
	{
		getline(in,stmp);
		temp.groups.push_back(stmp);
	}
	
	return in;
}
};
CGuser *user;
string name,pass;

cout<<"enter name:"<<endl
cin>>name;
cout<<"enter password"<<endl;
cin>>pass;
user= new CGuser(name,pass,0);
cout<<user;

the problem is with the last line, and what I mean problem is than it prints a number(I suspect the address in memory where user is allocated)instead of each field of the class
Another question that I have is how do I send over the network first just the item class, then the CGuser class(both client and server are the same endianess)

>cout<<user;
user is a pointer, you need to dereference it first:

cout << *user;

Though bare pointers are so passé. You should prefer smart pointers unless there's good reason to do otherwise:

string name, pass;
 
cout << "enter name: ";
cin >> name;

cout << "enter password: ";
cin >> pass;

auto_ptr<CGuser> user(new CGuser(name,pass,0));

cout << *user;

Note: auto_ptr is used in the example because you're guaranteed to have it available. However, it's problematic in terms of ownership and has actually been deprecated in the upcoming standard. The replacement in the new standard is unique_ptr. You can also use boost::shared_ptr or tr1::shared_pointer with current compilers.

so regarding my second question about sending it over a network; the v_friends,messages and groups fields are pointers to vectors, right?(so they will have only 4 bytes each ?) wouldn't that be a problem when I allocate a buffer with the size of the class(you know, to send it)?

Why the pointer in the first place? You could manage without it, can't you?

Well I think I can, but in this case I will need a default constructor for the class

Edited 5 Years Ago by CPT: n/a

wouldn't that be a problem when I allocate a buffer with the size of the class(you know, to send it)?

You need to read up on serialization. Real serialization, not this shallow copy crap.

Edited 5 Years Ago by Narue: n/a

You need to read up on serialization. Real serialization, not this shallow copy crap.

Well, I've tried to search with google and this is what I've found so far.I'm open to better serialization methods

Well, you don't seem to understand serialization at all if the problem is serializing a pointer rather than the pointed to data. The simplest method of serialization is converting the collective value of an object into a string. For example:

#include <boost/lexical_cast.hpp>
#include <iostream>
#include <string>
#include <vector>

using namespace std;

class foo {
    string _id;
    vector<int> _data;
public:
    foo(const string& id, const vector<int>& data);
    string to_string();
    foo& from_string(const string& s);
};

foo::foo(const string& id, const vector<int>& data)
    : _id(id), _data(data)
{}

string foo::to_string()
{
    string result(_id + "[");
    
    for (vector<int>::size_type i = 0; i < _data.size(); i++) {
        result += boost::lexical_cast<string>(_data[i]);
        
        if (i < _data.size() - 1)
            result += ",";
    }
    
    return result + "]";
}

foo& foo::from_string(const string& s)
{
    // Assuming s is formatted properly for brevity
    
    string::size_type begin = s.find_first_of("[");
    string::size_type end;
    
    _id = s.substr(0, begin);
    
    while ((end = s.find_first_of(++begin, ',')) != string::npos) {
        string data_field = s.substr(begin, end - begin);
        
        _data.push_back(boost::lexical_cast<int>(data_field));
    }
    
    return *this;
}

int main()
{
    vector<int> v;
    
    v.push_back(11);
    v.push_back(22);
    v.push_back(33);
    v.push_back(44);
    
    foo f1("test", v);
    string s = f1.to_string();
    foo f2 = f1.from_string(s);
    
    cout << s << '\n' << f2.to_string() << '\n';
}

Examples of real serialization methods or libraries are:

Boost.Serialization

Google's protobuf

JSON

Serialization requires two things: a way to deconstruct an object tree into a buffer from which the tree can be reconstructed (which usually requires some form of type identification), and a way to read and write the buffer that is compact, system-agnostic and easy to parse (e.g. XML, JSON, protobuf, etc.).

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