116 lines
2.0 KiB
Plaintext
116 lines
2.0 KiB
Plaintext
/* wf1 - print word frequencies; uses structures */
|
|
|
|
struct node {
|
|
int count; /* frequency count */
|
|
struct node *left; /* left subtree */
|
|
struct node *right; /* right subtree */
|
|
char *word; /* word itself */
|
|
} words[2000];
|
|
int next; /* index of next free entry in words */
|
|
|
|
struct node *lookup();
|
|
|
|
main()
|
|
{
|
|
struct node *root;
|
|
char word[20];
|
|
|
|
root = 0;
|
|
next = 0;
|
|
while (getword(word))
|
|
lookup(word, &root)->count++;
|
|
tprint(root);
|
|
return 0;
|
|
}
|
|
|
|
/* err - print error message s and die */
|
|
err(s)
|
|
char *s;
|
|
{
|
|
printf("? %s\n", s);
|
|
exit(1);
|
|
}
|
|
|
|
/* getword - get next input word into buf, return 0 on EOF */
|
|
int getword(buf)
|
|
char *buf;
|
|
{
|
|
char *s;
|
|
int c;
|
|
|
|
while ((c = getchar()) != -1 && isletter(c) == 0)
|
|
;
|
|
for (s = buf; c = isletter(c); c = getchar())
|
|
*s++ = c;
|
|
*s = 0;
|
|
if (s > buf)
|
|
return (1);
|
|
return (0);
|
|
}
|
|
|
|
/* isletter - return folded version of c if it is a letter, 0 otherwise */
|
|
int isletter(c)
|
|
int c;
|
|
{
|
|
if (c >= 'A' && c <= 'Z')
|
|
c += 'a' - 'A';
|
|
if (c >= 'a' && c <= 'z')
|
|
return (c);
|
|
return (0);
|
|
}
|
|
|
|
/* lookup - lookup word in tree; install if necessary */
|
|
struct node *lookup(word, p)
|
|
char *word;
|
|
struct node **p;
|
|
{
|
|
int cond;
|
|
char *malloc();
|
|
|
|
if (*p) {
|
|
cond = strcmp(word, (*p)->word);
|
|
if (cond < 0)
|
|
return lookup(word, &(*p)->left);
|
|
else if (cond > 0)
|
|
return lookup(word, &(*p)->right);
|
|
else
|
|
return *p;
|
|
}
|
|
if (next >= 2000)
|
|
err("out of node storage");
|
|
words[next].count = 0;
|
|
words[next].left = words[next].right = 0;
|
|
words[next].word = malloc(strlen(word) + 1);
|
|
if (words[next].word == 0)
|
|
err("out of word storage");
|
|
strcpy(words[next].word, word);
|
|
return *p = &words[next++];
|
|
}
|
|
|
|
/* tprint - print tree */
|
|
tprint(tree)
|
|
struct node *tree;
|
|
{
|
|
if (tree) {
|
|
tprint(tree->left);
|
|
printf("%d\t%s\n", tree->count, tree->word);
|
|
tprint(tree->right);
|
|
}
|
|
}
|
|
|
|
/* strcmp - compare s1 and s2, return <0, 0, or >0 */
|
|
int strcmp(s1, s2)
|
|
char *s1, *s2;
|
|
{
|
|
while (*s1 == *s2) {
|
|
if (*s1++ == 0)
|
|
return 0;
|
|
++s2;
|
|
}
|
|
if (*s1 == 0)
|
|
return -1;
|
|
else if (*s2 == 0)
|
|
return 1;
|
|
return *s1 - *s2;
|
|
}
|