Recursive function does not fully recurse object / sub-objects - c++

Question

I have a recursive function find() that tries to find a item with an given ID. Below I extracted the relevant parts from the class to make an example to compile:
#include <iostream>
#include <cstdarg>
#include <cstdio>
#include <string>
#include <vector>
class Item {
private:
std::vector<Item> subitems;
public:
std::wstring id;
public:
Item()
: subitems(0), id(L"") {}
Item(const Item& rhs)
: subitems(rhs.subitems.size()) {
for (std::size_t i = 0; i < rhs.subitems.size(); ++i)
subitems[i] = rhs.subitems[i];
id = rhs.id;
}
Item& operator==(const Item& rhs) {
if (this != &rhs) {
for (std::size_t i = 0; i < rhs.subitems.size(); ++i)
subitems[i] = rhs.subitems[i];
id = rhs.id;
}
return *this;
}
std::vector<Item> getSubitems() {
return subitems;
}
Item addSubitems(Item * item ...) {
va_list args;
va_start(args, item);
for (Item * arg = item; arg != NULL; arg = va_arg(args, Item *)) {
subitems.push_back(*item);
}
va_end(args);
return *this;
}
Item addSubitems(std::vector<Item>& items) {
for (typename std::vector<Item>::value_type &item : items) {
subitems.push_back(item);
}
return *this;
}
static Item * find(int id, std::vector<Item>& items) {
std::wstring id_str = std::to_wstring(id);
std::wcout << "--> find id=" << id_str << std::endl;
std::wcout << "size of items=" << items.size() << std::endl;
for (typename std::vector<Item>::value_type &c : items) {
std::wcout << "it .. cur id=" << c.id << std::endl;
if (!c.id.empty() && c.id == id_str) {
std::wcout << "==> found" << std::endl;
return &c;
}
if (!(c.getSubitems()).empty()) {
std::wcout << "-> find " << id << " in subitems" << std::endl;
std::vector<Item> subcls = c.getSubitems();
std::wcout << "size of subitems=" << subcls.size() << std::endl;
Item * sub = find(id, subcls);
if (sub != NULL) {
std::wcout << "==> found in subitems" << std::endl;
return sub;
}
}
}
return NULL;
}
};
int main() {
Item c1;
c1.id = L"0";
Item c2;
c2.id = L"1";
Item c3;
c3.id = L"2";
Item c4;
c4.id = L"3";
//std::vector<Item> cll4({c4});
//std::vector<Item> cll3({c3});
//std::vector<Item> cll2({c2});
c3.addSubitems(&c4, NULL);
c2.addSubitems(&c3, NULL);
c1.addSubitems(&c2, NULL);
//c1.addSubitems(cll2);
//c2.addSubitems(cll3);
//c3.addSubitems(cll4);
std::vector<Item> items({c1});
Item * c = Item::find(2, items);
std::wcout
<< "Found item="
<< ((c != NULL && c == &c3) ? "true" : "false") << std::endl;
std::wcout
<< ((c != NULL) ? c->id : L"") << std::endl;
return 0;
}
I create a few Items and add sub-Items to them. Now I want to be able to lookup an ID of an item and return the found item or sub-item object by using the recursive find() method.
If I add items with the addSubitems() (with variable args), it will find the item but doesn't return a (valid) item object. If I use the addSubitems method by passing a vector of items the find() method does not recurse fully all subitems.
Actually I am sitting on this problem now the last 4 hours and I am out of ideas, it might be a simple thing I oversee or miss. I added the copy constructor / and assignment operator afterwords (just to see if there are changes in behaviour), but no. Do not worry about the item ID being a string type (the reason is for later serialization), this class is in its early stages so I for now I chose a string type.
Could somebody please point me the flaws/problems to get this class straight! Thanks so much in advance!

Answer 1

Well, one problem with the "it will find the item but doesn't return a (valid) item object." is:
You send Item* to the addSubItems method and then you add a (*Item) to the vector;
This will initialize a copy c'tor, so later on, when you do is &c == &c3, obviously it would be false, since while the objects are INDEED identical, the addresses would not be since they are copies of one another.
Not that I understand why you would want to copy but the solution would be to either test
if (c == c3) -> activating the Item operator ==
OR allocate the members, save a
std::vector<Item*> subitems;
and then ask if (c == c3) -> asking about the addresses