Memory Leak using Tries - pset5 cs50 - dictionary.c - c

Question

I wrote a code for pset5 in CS50 course and was wondering if anyone could help me solve the problem of memory leak.
There is a program called speller.c that gets words from a text and use functions in dictionary.c (below) to look at another file (dictionary) and if the word is mispelled or not in the dictionary, it will printf all those words and calculate the running time of the whole program.
My code is actually working fine and I do get the correct output, but when I use valgrind, it says that memory is leaking. Why is this hapenning?
/**
* CS50 - PSET5 - user: linhobru
* Implements a dictionary's functionality.
*/
#include <stdbool.h>
#include <ctype.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/time.h>
#include "dictionary.h"
#define ALPHABETSIZE 27
typedef struct node
{
bool is_word;
struct node *children[ALPHABETSIZE];
}
node;
node *root = NULL;
int num_of_words = 0;
/**
* Returns true if word is in dictionary else false.
*/
bool check(const char *word)
{
node* next = root;
int k = ALPHABETSIZE;
for (int i = 0, len = strlen(word); i < len ; i++) // until (char) word[i] == '\0'
{
// verify letter and transform in index from 0 to 26
if (word[i] == '\'')
{
k = ALPHABETSIZE - 1;
}
else if (isalpha(word[i]))
{
k = tolower(word[i]) - 97;
}
if (next->children[k] == NULL)
{
return false;
}
else
{
next = next->children[k];
}
}
return next->is_word;
}
/**
* Loads dictionary into memory. Returns true if successful else false.
*/
bool load(const char *dictionary)
{
FILE *dict = fopen(dictionary, "r");
if (dict == NULL)
{
return false;
}
char word[LENGTH];
root = malloc(sizeof(node));
if (root == NULL)
{
unload();
fclose(dict);
return false;
}
while (fscanf(dict,"%s", word) != EOF)
{
node* now = root;
int k = ALPHABETSIZE;
for (int i = 0; word[i] != '\0'; i++)
{
// verify letter and transform in index from 0 to 26
if (word[i] == 39) // '\''
{
k = ALPHABETSIZE - 1;
}
else if (word[i] >= 97 && word[i] <= 122)
{
k = word[i] - 97;
}
/* else if (word[i] >= 65 && word[i] <= 90)
{
k = word[i] % 65;
}*/
else
{
fclose(dict);
return false;
}
if (now->children[k] == NULL)
{
node* new_node = malloc(sizeof(node));
now->children[k] = new_node;
}
now = now->children[k];
if (word[i + 1] == '\0')
{
now->is_word = true;
}
}
num_of_words++;
}
fclose(dict);
return true;
}
/**
* Returns number of words in dictionary if loaded else 0 if not yet loaded.
*/
unsigned int size(void)
{
return num_of_words;
}
/**
* Receives root at first and then each children to free.
*/
void unloadNode(node* next)
{
// call unloadNode on every node in this node's children
for(int i = 0; i < ALPHABETSIZE; i++)
{
if(next->children[i] != NULL)
{
unloadNode(next->children[i]);
}
}
// once the children nodes are freed, free this node
free(next);
}
/**
* Unloads dictionary from memory. Returns true if successful else false.
*/
bool unload(void)
{
unloadNode(root);
return true;
}
access to files in: https://github.com/linhobru/cs50psets/tree/master/workspace/pset5/speller/