Category : Files from Magazines
Archive : CUJ9410.ZIP
Filename : XREF.C
Output of file : XREF.C contained in archive : CUJ9410.ZIP
/* xref.c: Prints line numbers where each word occurs */
#include
#include
#include
#include
#define WORD_WIDTH 15
/* Node structure for each list of line numbers */
struct List
{
int lnum;
struct List *next;
};
typedef struct List List;
/* Node structure for tree of distinct words */
struct Tree
{
char word[WORD_WIDTH];
List *lstptr;
struct Tree *left,*right;
};
typedef struct Tree Tree;
/* Tree and list functions */
Tree *addword(Tree *, char *);
List *addline(List *, int);
Tree *find_node(Tree *, char *);
void print_tree(Tree *t);
void print_list(List *);
int ndistinct = 0;
main(int argc, char *argv[])
{
char linebuf[BUFSIZ];
Tree *words = NULL;
int lineno = 0;
/* Do optional input redirection */
if (argc > 1)
assert(freopen(argv[1],"r",stdin));
/* Process each line of text file */
while (fgets(linebuf,BUFSIZ,stdin) != NULL)
{
char *wordptr, *lineptr = linebuf;
char *bad_chars = " \t\n\f\v\\\"~!@#$%^&*()+'"
"|`1234567890-=\{}[]:;<>?,./";
++lineno;
/* Process each word in line */
while ((wordptr = strtok(lineptr,bad_chars)) != NULL)
{
Tree *node;
words = addword(words,wordptr);
node = find_node(words,wordptr);
node->lstptr = addline(node->lstptr,lineno);
lineptr = NULL;
}
}
/* Print results */
printf("No. of distinct words: %d\n\n",ndistinct);
print_tree(words);
return 0;
}
Tree *addword(Tree *tp, char *word)
{
if (tp == NULL)
{
/* Add new entry */
++ndistinct;
tp = malloc(sizeof(Tree));
strncpy(tp->word,word,WORD_WIDTH)[WORD_WIDTH] = '\0';
tp->left = tp->right = NULL;
tp->lstptr = NULL;
}
else if (strcmp(tp->word,word) < 0)
tp->right = addword(tp->right,word);
else if (strcmp(tp->word,word) > 0)
tp->left = addword(tp->left,word);
return tp;
}
List *addline(List *lp, int n)
{
if (lp == NULL)
{
/* Append new line number to list */
List *newp = malloc(sizeof(List));
assert(newp);
newp->lnum = n;
newp->next = NULL;
return newp;
}
else if (lp->lnum != n)
lp->next = addline(lp->next,n);
return lp;
}
void print_tree(Tree *tp)
{
if (tp != NULL)
{
/* Inorder traversal */
print_tree(tp->left);
printf("%-*.*s: ",WORD_WIDTH,WORD_WIDTH,tp->word);
print_list(tp->lstptr); putchar('\n');
print_tree(tp->right);
}
}
void print_list(List *lp)
{
const int NUM_WIDTH = 5;
const int INDENT = WORD_WIDTH + 2;
const int NUMS_PER_LINE = 8;
int count;
for (count = 0; lp != NULL; lp = lp->next, ++count)
{
printf("%*d",NUM_WIDTH,lp->lnum);
if ((count+1) % NUMS_PER_LINE == 0
&& lp->next != NULL)
printf("\n%*c",INDENT,' ');
}
}
Tree *find_node(Tree *tp, char *s)
{
/* Binary search for word */
if (strcmp(tp->word,s) > 0)
return find_node(tp->left,s);
else if (strcmp(tp->word,s) < 0)
return find_node(tp->right,s);
else
return tp;
}
Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!
This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.
But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/