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Commit 1f4f404

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minor tweaks
1 parent bc411df commit 1f4f404

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1 file changed

+92
-90
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+92
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‎chapter06/6-4.c

Lines changed: 92 additions & 90 deletions
Original file line numberDiff line numberDiff line change
@@ -5,14 +5,18 @@
55
* By Faisal Saadatmand
66
*/
77

8-
#include <stdio.h>
8+
/* NOTE: I included a definition for sorttree and copytree for academic
9+
* purposes. They are not used in the code */
10+
911
#include <ctype.h>
10-
#include <string.h>
12+
#include <stdio.h>
1113
#include <stdlib.h>
14+
#include <string.h>
1215

1316
#define MAXWORD 100
1417
#define BUFSIZE 100
1518

19+
/* types */
1620
struct tnode {
1721
char *word;
1822
int count;
@@ -22,98 +26,43 @@ struct tnode {
2226

2327
/* functions */
2428
int getword(char *, int);
25-
struct tnode *talloc(void); /* allocate memory to new tree node */
26-
char *strDup(char *); /* copy string into safe place */
29+
struct tnode *talloc(void); /* allocate memory to new tree node */
30+
char *strDup(char *); /* copy string into safe place */
2731
struct tnode *addtree(struct tnode *, char *);
28-
void treeprint(struct tnode *);
29-
struct tnode *copyTree(struct tnode *, struct tnode *);
30-
struct tnode *sortTree(struct tnode *, struct tnode *);
31-
struct tnode *freetree(struct tnode *);
32+
void printtree(struct tnode *);
33+
void freetree(struct tnode *);
34+
struct tnode *sorttree(struct tnode *, struct tnode *); /* optional */
3235

3336
/* globals */
34-
int buf[BUFSIZE]; /* buffer from ungetch */
35-
int bufp = 0; /* next free position in buf */
36-
37-
int getch(void) /* get a (possibly pushed back) character */
38-
{
39-
return (bufp > 0) ? buf[--bufp] : getchar();
40-
}
41-
42-
void ungetch(int c) /* push character back on input */
43-
{
44-
if (bufp >= BUFSIZE)
45-
printf("ungetch: too many characters\n");
46-
else
47-
buf[bufp++] = c;
48-
}
49-
50-
/* getword: get next word or character from input */
51-
int getword(char *word, int lim)
52-
{
53-
int c, getch(void);
54-
void ungetch(int);
55-
char *w = word;
56-
57-
while (isspace(c = getch()))
58-
;
59-
if (c != EOF)
60-
*w++ = c;
61-
if (!isalpha(c)) {
62-
*w = '0円';
63-
return c;
64-
}
65-
for ( ; --lim > 0; w++)
66-
if (!isalnum(*w = getch())) {
67-
ungetch(*w);
68-
break;
69-
}
70-
*w = '0円';
71-
return word[0];
72-
}
73-
74-
/* talloc: make a tnode */
75-
struct tnode *talloc(void)
76-
{
77-
return malloc(sizeof(struct tnode));
78-
}
79-
80-
/*strDup: make a duplicate of s */
81-
char *strDup(char *s)
82-
{
83-
char *p;
84-
85-
p = malloc(strlen(s) + 1); /* +1 for '0円' */
86-
if (p)
87-
strcpy(p, s);
88-
return p;
89-
}
37+
int buf[BUFSIZE]; /* buffer from ungetch */
38+
int bufp = 0; /* next free position in buf */
9039

9140
/* addtree: add a node with w, at or below p */
9241
struct tnode *addtree(struct tnode *p, char *w)
9342
{
9443
int cond;
9544

96-
if (!p) { /* a new word has arrived */
45+
if (!p) { /* a new word has arrived */
9746
p = talloc(); /* make a new node */
9847
p->word = strDup(w); /* copy data to it */
9948
p->count = 1;
10049
p->left = p->right = NULL;
101-
} else if ((cond = strcmp(w, p->word))==0)
102-
p->count++; /* repeated word */
50+
} else if (!(cond = strcmp(w, p->word)))
51+
++p->count; /* repeated word */
10352
else if (cond < 0) /* less than into left subtree */
10453
p->left = addtree(p->left, w);
10554
else
10655
p->right = addtree(p->right, w);
10756
return p;
10857
}
10958

110-
/* print: in-order print of tree p */
111-
void treeprint(struct tnode *p)
59+
/* print: in-order print of tree p - decreasing order version */
60+
void printtree(struct tnode *p)
11261
{
11362
if (p) {
114-
treeprint(p->right);
63+
printtree(p->right);
11564
printf("%4d %s\n", p->count, p->word);
116-
treeprint(p->left);
65+
printtree(p->left);
11766
}
11867
}
11968

@@ -132,45 +81,98 @@ struct tnode *copyTree(struct tnode *p, struct tnode *root)
13281
return p;
13382
}
13483

135-
/* sortTree: performs inorder traversal on root and creates a BST p according
84+
/* sorttree: performs inorder traversal on root and creates a BST p according
13685
* to frequency of occurrence */
137-
struct tnode *sortTree(struct tnode *p, struct tnode *root)
86+
struct tnode *sorttree(struct tnode *p, struct tnode *root)
13887
{
88+
struct tnode *copyTree(struct tnode *, struct tnode *);
89+
13990
if (root) {
140-
p = sortTree(p, root->left);
91+
p = sorttree(p, root->left);
14192
p = copyTree(p, root);
142-
p = sortTree(p, root->right);
93+
p = sorttree(p, root->right);
14394
}
14495
return p;
14596
}
14697

98+
/* talloc: make a tnode */
99+
struct tnode *talloc(void)
100+
{
101+
return malloc(sizeof(struct tnode));
102+
}
103+
104+
/*strDup: make a duplicate of s */
105+
char *strDup(char *s)
106+
{
107+
char *p;
108+
109+
p = malloc(strlen(s) + 1); /* +1 for '0円' */
110+
if (p)
111+
strcpy(p, s);
112+
return p;
113+
}
114+
147115
/* freetree: free allocated heap memory of node tree */
148-
structtnode*freetree(struct tnode *node)
116+
voidfreetree(struct tnode *node)
149117
{
150-
if (node) {
151-
freetree(node->left);
152-
freetree(node->right);
153-
free(node->word);
154-
free(node);
118+
if (!node)
119+
return;
120+
freetree(node->left);
121+
freetree(node->right);
122+
free(node->word);
123+
free(node);
124+
}
125+
126+
/* getword: get next word or character from input */
127+
int getword(char *word, int lim)
128+
{
129+
int c, getch(void);
130+
void ungetch(int);
131+
char *w = word;
132+
133+
while (isblank(c = getch()))
134+
;
135+
if (c != EOF)
136+
*w++ = c;
137+
if (!isalpha(c)) {
138+
*w = '0円';
139+
return c;
155140
}
156-
return node;
141+
for ( ; --lim > 0; w++)
142+
if (!isalnum(*w = getch())) {
143+
ungetch(*w);
144+
break;
145+
}
146+
*w = '0円';
147+
return word[0];
148+
}
149+
150+
/* get a (possibly pushed back) character */
151+
int getch(void)
152+
{
153+
return (bufp > 0) ? buf[--bufp] : getchar();
154+
}
155+
156+
/* push character back on input */
157+
void ungetch(int c)
158+
{
159+
if (bufp >= BUFSIZE)
160+
printf("ungetch: too many characters\n");
161+
else
162+
buf[bufp++] = c;
157163
}
158164

159165
int main(void)
160166
{
161167
struct tnode *root; /* root node */
162-
struct tnode *sorted; /* root node to sorted tree */
163168
char word[MAXWORD]; /* currently read word */
164169

165-
root = sorted=NULL;
170+
root = NULL;
166171
while (getword(word, MAXWORD) != EOF)
167172
if (isalpha(word[0]))
168173
root = (addtree(root, word)); /* build tree */
169-
sorted = sortTree(sorted, root);
170-
treeprint(sorted);
171-
/* clean up */
172-
root = freetree(root);
173-
sorted = freetree(sorted);
174-
root = sorted = NULL;
174+
printtree(root);
175+
freetree(root);
176+
root = NULL;
175177
return 0;
176178
}

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