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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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vol_300
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347_01
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example2.c
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1991-10-20
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/*
* program: Example2
* purpose: Test shell for threaded avl-tree. Program reads a file
* which contains a list of words, one per line. As words
* are read, they are written to monitor screen and inserted
* into the threaded AVL tree. After file is read, a prompt
* line is written to the bottom of the screen, and user is
* presented with choices. Additional words may be inserted,
* tree can be searched for a word, the tree can listed in
* forward or reverse order, words may be deleted from the
* tree, the predecessor or successor of the last found word
* may be listed.
*
* Usage: Example2 <filename> where filename is the name of a
* text file which contains left-adjusted
* words, one per line.
*
* Copyright (c) 1990, 1991 Bert C. Hughes
* 200 N. Saratoga
* St.Paul, MN 55104
* Compuserve 71211,577
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "tavltree.h"
#if defined __TURBOC__
#include <conio.h>
#else
#define cprintf printf
int getche(void)
{
char s[128];
gets(s);
return (strlen(s) ? s[0] : '\n');
}
#endif
void list(TAVL_treeptr , TAVL_nodeptr (*)(TAVL_nodeptr));
main (int argc, char *argv[])
{
char s[128];
FILE *fp;
TAVL_treeptr tree;
TAVL_nodeptr p;
int cmpfunc();
void *id();
void *cpy();
void *rdstr();
TAVL_nodeptr (*dirfunc)(TAVL_nodeptr);
#if defined __TURBOC__
directvideo = 0; /* change to 1 if there is "snow" on your screen */
#endif
/* open a file which contains a list of words, one per line */
if (argc < 2)
strcpy(s,"WORDLIST");
else
strcpy(s,argv[1]);
if ((fp = fopen(s,"r")) == NULL) {
cprintf("Unable to open file: %s\r\n",s);
exit(1);
}
/* initialize the tree */
if ((tree = tavl_init(cmpfunc,id,cpy,free,rdstr,malloc,free)) == NULL) {
cprintf("\r\nError initializing tree.");
exit(1);
}
while (!(fscanf(fp,"%s",s) == EOF)) {
cprintf("%-16.14s",s);
if (tavl_insert(tree,s,0) == NULL) {
cprintf("\r\nError inserting into tree.");
exit(1);
}
}
fclose(fp);
/* Several cases of direct use of a field of TAVL_NODE below. */
/* All TAVL fields are READONLY! Only tavl-library routines */
/* alter tree & node field values. */
p = tavl_reset(tree);
do {
#if !defined __TURBOC__
printf("\n ...press selection key, then <ENTER> ...");
#endif
cprintf("\r\n\:select: <I>nsert <F>ind <D>elete <L>ist <S>ucc <P>red <Q>uit ");
switch (getche()) {
case 'I': case 'i':
cprintf("\r\nInsert: ");
gets(s);
tavl_insert(tree,s,1);
break;
case 'F': case 'f':
cprintf("\r\nFind: ");
p = tavl_find(tree,gets(s));
if (p != NULL)
cprintf("\r\nfind OK: %s\r\n",p->dataptr);
else
cprintf("\r\nNot found.\r\n");
break;
case 'D': case 'd':
cprintf("\r\nDelete: ");
gets(s);
tavl_delete(tree,s);
break;
case 'L': case 'l':
cprintf("\r\n<F>orward or <R>everse? ");
if (getche() != 'r')
dirfunc = tavl_succ;
else
dirfunc = tavl_pred;
cprintf("\r\n");
list(tree,dirfunc);
break;
case 'S': case 's':
if ((p = tavl_succ(p)) != NULL)
cprintf("\r\n\nSuccessor: %s\r\n",p->dataptr);
else
cprintf("\r\n\nNo more.\r\n");
break;
case 'P': case 'p':
if ((p = tavl_pred(p)) != NULL)
cprintf("\r\n\nPredecessor: %s\r\n",p->dataptr);
else
cprintf("\r\n\nNo more.\r\n");
break;
case 'Q': case 'q':
tavl_destroy(tree);
exit(0);
default:
cprintf("\r\n");
}
} while (1);
}
int cmpfunc(void *p, void *q)
/* function compares two identifiers. Required parameter of tavl_init */
{
return strcmp(p,q);
}
void *id(void *s)
/* function returns identifier of items inserted into tree,
which in this case are simply strings.
*/
{
return s;
}
void *cpy(void *p)
/* create a copy of data item p - which must be a string in this example. */
{
int size = 1 + strlen(p);
char *s = malloc(size);
return(memcpy(s,p,size));
}
void *rdstr(char *dest, const char *src)
{
return((void *)strcpy(dest,src));
}
void list(TAVL_treeptr tree, TAVL_nodeptr (*f)(TAVL_nodeptr))
{
TAVL_nodeptr p = tavl_reset(tree);
long i = 0;
while ((p = (*f)(p)) != NULL) {
#if defined __TURBOC__
/* TurboC users can stop the output... */
if (kbhit()) {
while (kbhit())
getch(); /* remove it */
cprintf("\r\n\nHalt? <y/n> ");
if (getche() == 'y') {
cprintf("\r\n\n");
i = -1;
break;
}
cprintf("\r\n\n");
}
#endif
cprintf("%-16.14s",p->dataptr);
i++;
}
cprintf("\r\n >> %ld items in TAVLtree <<\r\n",i);
}