cs50 pset4 speller trie word too long "index 46 out of bounds for type 'char [46]'". Isn't that handled by the code already written?

Question

My code is giving all the right answers (lalaland.txt), but valgrind says: ==9947== dictionary.c:69:25: runtime error: index 46 out of bounds for type 'char [46]'

(and I printf the problem - too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT.)

valgrind continues: dictionary.c:72:29: runtime error: index 46 out of bounds for type 'char [46]'

(and printf continues: too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT. too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT. too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT. too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT. too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT. too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT. too many letters in word AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHT.)

==9947== Invalid read of size 4

my code is:

#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "dictionary.h"


// Represents number of children for each node in a trie
#define N 27

// Represents a node in a trie
typedef struct node
{
    bool is_word;
    struct node *children[N];
}
node;

// Represents a trie
node *root;

// Function declaration
void freedom(node* trvl);

// Word coounter
int words = 0;

// Loads dictionary into memory
bool load(const char *dictionary)
{
    // Initialize trie
    root = malloc(sizeof(node));
    if (root == NULL)
    {
        return false;
    }

    root->is_word = false;

    for (int i = 0; i < N; i++)
    {
        root->children[i] = NULL;
    }

    // Open dictionary
    FILE *file = fopen(dictionary, "r");
    if (file == NULL)
    {
        unload();
        return false;
    }

    // Buffer for a word
    char word[LENGTH + 1];

    // Insert words into trie
    while (fscanf(file, "%s", word) != EOF)
    {
        // TODO
        // create a travelling node to walk the trie
        node *trvl = root;
        // create index of letter in word
        int index;

        for (int i = 0; word[i] != '\0'; i++)
        {
            if (i > 45){printf("too many letters in word %s\n", word);}
            index = tolower(word[i]) - 'a';
            if (index < 0 || index > 26)
            {
                index = 26;
            }

            if (trvl->children[index] == NULL)
            {
                // create new node
                trvl->children[index] = malloc(sizeof(node));

                for (int j = 0; j < N; j++)
                {
                    trvl->children[index]->children[j] = NULL;
                }
            }

            // traverse to node
            trvl = trvl->children[index];
        }

        // mark the last node as a word
        trvl->is_word = true;
        words++;
    };

    // Close dictionary
    fclose(file);

    // Indicate success
    return true;
}

// Returns number of words in dictionary if loaded else 0 if not yet loaded
unsigned int size(void)
{
    // TODO
    return words;
}

// Returns true if word is in dictionary else false
bool check(const char *word)
{
    // TODO
    // Variable to hold letter index
    int index;

    // protect the root, create a travel trie
    node *trvl = root;

    // Check word letter by letter, comparing to the dictionary
    //  Moving into the next node each time, return false if path doesn't match
    for (int i = 0, len = strlen(word); i < len; i++)
    {
        index = tolower(word[i]) - 'a';
        if (index < 0)
        {
            index = 26;
        }

        if (trvl->children[index] == NULL)
        {
            return false;
        }
        else
        {
            trvl = trvl->children[index];
        }
    }

    if (trvl->is_word == true)
    {
        return true;
    }
    else
    {
        return false;
    }
}

// Unloads dictionary from memory, returning true if successful else false
bool unload(void)
{
    // TODO
    // create a function to free nodes
    // has to be a function so I can call it recursively
    (freedom(root));
    return true;
}

void freedom(node* trvl)
{
    for (int i = 0; i< N; i++)
    {
        if (trvl->children[i] != NULL)
        {
            freedom(trvl->children[i]);
        }
    }
    free(trvl);
}

Answer 1

For this problem, the dictionary is guaranteed to not have any words longer than LENGTH (which is defined in dictionary.h:

// Maximum length for a word
// (e.g., pneumonoultramicroscopicsilicovolcanoconiosis)
#define LENGTH 45

So if you send it a word longer than that, your program will have an error that you've seen.