Initialising a struct that contains a vector of itself

Question

I have a menu system that I want to initialise from constant data. A MenuItem can contain, as a sub-menu, a vector of MenuItems. But it only works

Answer 1

what you are trying to do is an upcomingcurrent feature of C++ called "initializer lists", where a vector or list can be initialized with = { }. I don't know if they have come out with it in TR1 or not. maybe it's in TR2.

#include 
#include 
#include 
using namespace std;
int main(void) {
    vector vi = {1, 2, 3, 4, 5};
    list li = {5, 4, 3, 2, 1, 0};
    cout<<"vector size="<

#include 
#include 
#include 
void * pRoot = NULL; //pointer to CTree
class CTreenode;
class CTree;
class CTree {
    public:
        vector lctnNodeList; //list does not have at() or operator[]
        vector::iterator lctni;
    public:
        CTree() {}
        ~CTree() {
            for (lctni=lctnNodeList.begin(); lctni != lctnNodeList.end(); nctni++) {
                if (NULL==lctni->getChildPtr()) {
                    //do nothing, we have already done all we can
                } else {
                    delete (CTree *)lctnNodeList.pChild;
                }
                //do action here
            }
        }
        void addToList(string& data, CTree * p) { 
            CTreeNode ctn(data, p);
            lctnNodeList.push_back(d); 
        }
        void eraseAt(size_t index) { 
            vector::iterator i = lctnNodeList.begin();
            vector::iterator i2 = lctnNodeList.begin();
            i2++;
            size_t x;
            for (x=0; x <= index; x++,i++,i2++) {
                if (index == x) {
                    lctnNodeList.erase(i,i2);
                    break;
                }
            }
        }
        void at(size_t index, string& returndata, CTree * &p) { 
            vector::iterator i = lctnNodeList.begin();
            size_t x;
            for (x=0; x <= index; i++,x++) {
                if (x==index) {
                     i->getData(returndata, p);
                     break;
                }
            }
        }
        const CTreeNode& operator[](const size_t idx) {
            if (idx < lctnNodeList(size)) {
                return lctnNodeList.at(idx);
            } else {
                //throw an error
            }
        }
        const size() {
            return lctnNodeList.size();
        }
        //this can be applied to the root of the tree (pRoot).
        doActionToThisSubtree(void * root) {
            CTree * pct = (CTree *)root;
            for (pct->lctni=pct->lctnNodeList.begin(); pct->lctni != pct->lctnNodeList.end(); pct->nctni++) {
                //this is a depth-first traversal.
                if (NULL==pct->lctni->getChildPtr()) {
                    //do nothing, we have already done all we can
                    //we do this if statement to prevent infinite recursion
                } else {
                    //at this point, recursively entering child domain
                    doActionToThisSubtree(pct->lctni->getChildPtr());
                    //at thisd point, exiting child domain
                }
                //do Action on CTreeNode node pct->lctni-> here.
            }
        }
};
class CTreeNode {
    public:
        CTree * pChild; //CTree *, may have to replace with void *
        string sData;
    public:
        CTreeNode() : pChild(NULL) {}
        CTreeNode(string& data, pchild) : pChild(pchild) {
            sData = data;
        }
        ~CTreeNode() { 
             if (NULL!=pChild) { 
                 delete pChild;//delete (CTree *)pChild; 
                 pChild = NULL; 
             }
        void getChild(CTreeNode& child) { 
            child = *pChild;//child = *((CTree *)pChild); 
        }
        bool addChild(string& s) { 
            if (NULL==pChild) {
                return false;
            } else {
                pChild = new CTree;
            }
            return true;
        }
        void * getChildPtr() { return pChild; }
        void getData(string& data, CTree * &p) { //not sure about how to put the & in there on CTree
            data=sData;
            p = pChild;
        }
        void setData(string& data, CTree * p) {
            sData=data;
            pChild = p;
        }
};


the problem is mutual dependency here, and I think I have it resolved with the class declaration.
do class CTreeNode; before class CTree {}.
http://www.codeguru.com/forum/showthread.php?t=383253

I am probably mangling this code, and it's incomplete, because I haven't had the need to write a tree in years, but I think I've covered the basics.  I didn't implement operator[].