exercise 6-3

Author: Heatwave

chapter-6-structures/7.words-appear-lines.c

@@ -0,0 +1,121 @@
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define MAXWORD 100
+#define MAX_LINES 100
+
+struct tnode {
+	char *word;
+	int count;
+	int lines[MAX_LINES];
+	struct tnode *left;
+	struct tnode *right;
+};
+
+struct tnode *addtree(struct tnode *, char *);
+void treeprint(struct tnode *);
+int getword(char *, int);
+
+static int current_line = 1;
+
+// gcc 7.words-appear-lines.c getch.c
+main()
+{
+	struct tnode *root;
+	char word[MAXWORD];
+
+	root = NULL;
+	while (getword(word, MAXWORD) != EOF)
+		if (isalpha(word[0]))
+			root = addtree(root, word);
+	treeprint(root);
+
+	return 0;
+}
+
+int getword(char *word, int lim)
+{
+	int c, getch(void);
+	void ungetch(int);
+	char *w = word;
+
+	do {
+		c = getch();
+		if (c == '\n')
+			++current_line;
+	} while (isspace(c));
+
+	if (c != EOF)
+		*w++ = c;
+	if (!isalpha(c)) {
+		*w = '\0';
+		return c;
+	}
+	for ( ; --lim > 0; w++)
+		if (!isalnum(*w = getch()) && *w != '_') {
+			ungetch(*w);
+			break;
+		}
+	*w = '\0';
+	return word[0];
+}
+
+struct tnode *talloc(void);
+char *mystrdup(char *s);
+
+struct tnode *addtree(struct tnode *p, char *w)
+{
+	int cond;
+	int i;
+
+	if (p == NULL) {
+		p = talloc();
+		p->word = mystrdup(w);
+		p->count = 1;
+		p->lines[0] = current_line;
+		p->left = p-> right = NULL;
+	} else if ((cond = strcmp(w, p->word)) == 0) {
+		p->count++;
+		i = 0;
+		while (p->lines[i] != 0)
+			++i;
+		//printf("i: %d\n", i);
+		p->lines[i] = current_line;
+	} else if (cond < 0)
+		p->left = addtree(p->left, w);
+	else
+		p->right = addtree(p->right, w);
+	return p;
+}
+
+void treeprint(struct tnode *p)
+{
+	int i = 0;
+	if (p != NULL) {
+		treeprint(p->left);
+		printf("%4d %s ", p->count, p->word);
+		while (p->lines[i] != 0 && i < MAX_LINES)
+			printf("%d ", p->lines[i++]);
+		printf("\n");
+		treeprint(p->right);
+	}
+}
+
+struct tnode *talloc(void)
+{
+	return (struct tnode *) malloc(sizeof(struct tnode));
+}
+
+char *mystrdup(char *s)
+{
+	char *p;
+
+	p = (char *) malloc(strlen(s)+1);
+	if (p != NULL)
+		strcpy(p, s);
+
+	return p;
+}
+