Use of undeclared identifier with Scope Resolution Operators and Header File

[codeTocode]

Hello, I've been trying to get this Trie program to work for a while, and keep getting the same error "Use of undeclared identifier" for the four functions in my class. I think the header file is set up correctly, and I've used scope resolution operators for each function in the .cpp file. I cannot figure out what else is causing this problem. All help is appreciated!

#include <iostream>
#include <string>
#include "TrieNode.h"
using namespace std;

int main()
{
string keys[] = {"sunny", "raining", "happy", "sad"};
int n = sizeof(keys)/sizeof(keys[0]);

TrieNode *root = getNode();

// Construct trie
for (int i = 0; i < n; i++)
insertNode(root, keys[i]);

// Search for different keys
searchTrie(root, "the")? cout << "Yes\n" :
cout << "No\n";
searchTrie(root, "these")? cout << "Yes\n" :
cout << "No\n";
}

#include<string>
using namespace std;

const int ALPHABET_SIZE = 26;
const int CASE = 'a';

class TrieNode
{
public:
TrieNode* children[ALPHABET_SIZE];
bool isEndOfWord; //true if node represents end of word.

TrieNode();
TrieNode *getNode();
void insertNode(TrieNode *root, string key);
bool searchTrie(TrieNode *root, string key);
};

#include <iostream>
#include <string>
#include "TrieNode.h"
using namespace std;


TrieNode::TrieNode()
{
getNode();
}

TrieNode* TrieNode::getNode()
{
TrieNode *nodePointer = NULL;
nodePointer->isEndOfWord = false;

for (int i = 0; i < ALPHABET_SIZE; i++)
nodePointer->children[i] = NULL;

return nodePointer;
}

void TrieNode::insertNode(TrieNode *root, string word)
{
TrieNode *searchPointer = root; //points to the trie we are working with

for (int i = 0; i < word.length(); i++)
{
int index = word[i] - CASE;
if (!searchPointer->children[index])
searchPointer->children[index] = getNode();

searchPointer = searchPointer->children[index];
}

searchPointer->isEndOfWord = true;
}

bool TrieNode::searchTrie(TrieNode *root, string word)
{
TrieNode *searchPointer = root;
for (int i = 0; i < word.length(); i++)
{
int index = word[i] - CASE;
if (!searchPointer->children[index])
return false;

searchPointer = searchPointer->children[index];
}

return (searchPointer != NULL && searchPointer->isEndOfWord);
}

[Peter87]

In the main function you need to call getNode() on a TrieNode object.

E.g.

TrieNode someTrieNodeObject;
TrieNode *root = someTrieNodeObject.getNode();

I'm not sure what the getNode() function is supposed to do but it's not working. You declare a null pointer and then you try to use it to access stuff but that won't work because null means the pointer doesn't point to anything.