define dynamic array inside a struct without causing a segmentation fault - struct

Question

I'm new to c++ and I have to work with dynamic arrays:| I need to define a few dynamic arrays inside my header file and access them from main. The problem is that when I'm defining the arrays inside the structs, I get segmentation faults and don't know how to fix them.
Below is my header file.
I'm aware that there are lots of problems with my code and I could use your help. I'm really stuck here.
Thanks in advance.
I expect this code to work fine with dynamic arrays just like it does with vectors. But it's not.
`
#pragma once
#include <iostream>
#include <functional>
#include <algorithm>
#define children_link_Size 149
#define row 15
#define col 100
using namespace std;
int itemListIndex = 0;
int freqIdx = 0;
int childIdx = 0;
int linkIdx = 0;
namespace std {
template <typename T> T* begin(std::pair<T*, T*> const& p)
{
return p.first;
}
template <typename T> T* end(std::pair<T*, T*> const& p)
{
return p.second;
}
}
struct Node
{
int itemValue{};
int order{ 0 };
int freq{ 0 };
Node* parent{ nullptr };
Node* children{};
Node* links{};
Node() {
children = new Node[children_link_Size];
links = new Node[children_link_Size];
}
explicit Node(int const& p_value, int p_order = 0) :itemValue(p_value), order(p_order)
{
++freq;
cout << " + " << itemValue << " (" << order << ")" << endl;
}
bool operator ==(Node const& p_node) const
{
return itemValue == p_node.itemValue;
}
~Node() {
delete[] children;
delete[] links;
}
};
/*struct mySet {
Node* OrderedItems;
mySet()
{
OrderedItems = new Node[uniqueSize];
}
void insert(Node item)
{
for (int i = 0; i < uniqueSize; i++)
{
for (int j = 0; j < i; j++)
{
if (item == OrderedItems[j])
{
break;
}
else
{
OrderedItems[i] = item;
}
}
}
}
~mySet()
{
delete[] OrderedItems;
}
};*/
struct ItemSupport
{
explicit ItemSupport(int p_minSup) { ItemSupport::minSup = p_minSup; }
Node* Itemset = new (nothrow) Node[row];
Node* OrderedItems = new (nothrow) Node[row];
ItemSupport& operator<<(int const& p_itemValue)
{
static int order = 0;
auto inode = find_if(Itemset, Itemset + row, [&p_itemValue](Node const& p_node)
{
return p_node.itemValue == p_itemValue;
});
if (inode == Itemset + row)
{
Node node(p_itemValue, order);
Itemset[itemListIndex] = node;
itemListIndex++;
++order;
}
else
{
auto& node = (*inode);
++node.freq;
}
return *this;
}
friend ostream& operator<<(ostream& p_os, ItemSupport const& p_itemSupport)
{
ItemSupport* NoDe = {0};
if (NoDe)
{
NoDe->OrderedItems = p_itemSupport.getFrequentItems();
for (Node node : std::make_pair(NoDe->OrderedItems, NoDe->OrderedItems + row))
{
p_os << node.itemValue << ": support " << node.freq << ", order " << node.order << endl;
}
return p_os;
}
}
Node* getItem(int const& p_itemValue)
{
auto inode = find_if(Itemset, Itemset + row, [&p_itemValue](Node const& p_node)
{
return p_node.itemValue == p_itemValue;
});
if (inode != Itemset + row)
{
Node* node = const_cast<Node*>(&(*inode));
return node;
}
return nullptr;
}
static int getMinSup()
{
return minSup;
}
static int minSup;
private:
Node* getFrequentItems() const
{
int j = 0;
for (int i = 0; i < row; i++)
{
if (Itemset[i].freq >= minSup)
OrderedItems[j++] = Itemset[i];
}
return OrderedItems;
}
Node* getUnfrequentItems() const
{
int j = 0;
for (int i = 0; i < row; i++)
{
if (Itemset[i].freq <= minSup)
OrderedItems[j++] = Itemset[i];
}
return OrderedItems;
}
/*~ItemSupport() {
//delete[] Itemset;
//delete[] OrderedItems;
}*/
};
int ItemSupport::minSup = 0;
struct FP_Tree
{
explicit FP_Tree(ItemSupport& p_itemSupport, const int& p_rootValue = int()) :_headItemSupport(p_itemSupport)
{
_root = new Node(p_rootValue);
}
//void construct(Transaction const& p_itemValues)
void construct(int *p_itemValues)
{
// A. Order items into transaction
ItemSupport* ordered = {0};
for (int const& itemValue : std::make_pair(p_itemValues, p_itemValues + row))
{
Node* pNode = _headItemSupport.getItem(itemValue);
if (pNode && pNode->freq >= ItemSupport::getMinSup())
{
if (ordered)
{
ordered->OrderedItems[freqIdx] = *pNode;
freqIdx++;
}
}
}
// B. Create FP_TREE
Node* actualNode = _root;
bool here = true;
string tab;
if (ordered)
{
for (Node const& node : std::make_pair(ordered->OrderedItems, ordered->OrderedItems + row))
{
tab += "\t-";
auto it = actualNode->children;
if (here)
{
auto it = find_if(actualNode->children,
actualNode->children + children_link_Size,
[&node](Node const& nodeTmp) {
return node == (nodeTmp);
});
here &= it != actualNode->children + children_link_Size;
}
if (here)
{
actualNode = it;
++actualNode->freq;
}
else
{
Node* pNode = new Node(node.itemValue);
actualNode->children[childIdx++] = *pNode;
pNode->parent = actualNode;
Node* pNodeHead = _headItemSupport.getItem(node.itemValue);
pNodeHead->links[linkIdx++] = *pNode;
actualNode = pNode;
delete pNode;
}
//cout << tab << actualNode->_itemValue << "(" << actualNode->_freq << ")" << endl;
}
}
//cout << endl;
}
ItemSupport& headItemSupport() const
{
return _headItemSupport;
}
public:
Node* root() const
{
return _root;
}
private:
ItemSupport& _headItemSupport;
Node* _root;
};
`

Answer 1

I expect this code to work fine with dynamic arrays just like it does with vectors
Since you are using C++, do use std::vector -- it will save you a lot of trouble and there is no reason not to.