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//===-- dictionary.c ---------------------------------------------*- C -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===---------------------------------------------------------------------===//
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
typedef struct tree_node
{
const char *word;
struct tree_node *left;
struct tree_node *right;
} tree_node;
/* Given a char*, returns a substring that starts at the first
alphabet character and ends at the last alphabet character, i.e. it
strips off beginning or ending quotes, punctuation, etc. */
char *
strip (char **word)
{
char *start = *word;
int len = strlen (start);
char *end = start + len - 1;
while ((start < end) && (!isalpha (start[0])))
start++;
while ((end > start) && (!isalpha (end[0])))
end--;
if (start > end)
return NULL;
end[1] = '\0';
*word = start;
return start;
}
/* Given a binary search tree (sorted alphabetically by the word at
each node), and a new word, inserts the word at the appropriate
place in the tree. */
void
insert (tree_node *root, char *word)
{
if (root == NULL)
return;
int compare_value = strcmp (word, root->word);
if (compare_value == 0)
return;
if (compare_value < 0)
{
if (root->left != NULL)
insert (root->left, word);
else
{
tree_node *new_node = (tree_node *) malloc (sizeof (tree_node));
new_node->word = strdup (word);
new_node->left = NULL;
new_node->right = NULL;
root->left = new_node;
}
}
else
{
if (root->right != NULL)
insert (root->right, word);
else
{
tree_node *new_node = (tree_node *) malloc (sizeof (tree_node));
new_node->word = strdup (word);
new_node->left = NULL;
new_node->right = NULL;
root->right = new_node;
}
}
}
/* Read in a text file and storea all the words from the file in a
binary search tree. */
void
populate_dictionary (tree_node **dictionary, char *filename)
{
FILE *in_file;
char word[1024];
in_file = fopen (filename, "r");
if (in_file)
{
while (fscanf (in_file, "%s", word) == 1)
{
char *new_word = (strdup (word));
new_word = strip (&new_word);
if (*dictionary == NULL)
{
tree_node *new_node = (tree_node *) malloc (sizeof (tree_node));
new_node->word = new_word;
new_node->left = NULL;
new_node->right = NULL;
*dictionary = new_node;
}
else
insert (*dictionary, new_word);
}
}
}
/* Given a binary search tree and a word, search for the word
in the binary search tree. */
int
find_word (tree_node *dictionary, char *word)
{
if (!word || !dictionary)
return 0;
int compare_value = strcmp (word, dictionary->word);
if (compare_value == 0)
return 1;
else if (compare_value < 0)
return find_word (dictionary->left, word);
else
return find_word (dictionary->right, word);
}
/* Print out the words in the binary search tree, in sorted order. */
void
print_tree (tree_node *dictionary)
{
if (!dictionary)
return;
if (dictionary->left)
print_tree (dictionary->left);
printf ("%s\n", dictionary->word);
if (dictionary->right)
print_tree (dictionary->right);
}
int
main (int argc, char **argv)
{
tree_node *dictionary = NULL;
char buffer[1024];
char *filename;
int done = 0;
if (argc == 2)
filename = argv[1];
if (!filename)
return -1;
populate_dictionary (&dictionary, filename);
fprintf (stdout, "Dictionary loaded.\nEnter search word: ");
while (!done && fgets (buffer, sizeof(buffer), stdin))
{
char *word = buffer;
int len = strlen (word);
int i;
for (i = 0; i < len; ++i)
word[i] = tolower (word[i]);
if ((len > 0) && (word[len-1] == '\n'))
{
word[len-1] = '\0';
len = len - 1;
}
if (find_word (dictionary, word))
fprintf (stdout, "Yes!\n");
else
fprintf (stdout, "No!\n");
fprintf (stdout, "Enter search word: ");
}
fprintf (stdout, "\n");
return 0;
}
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