1 files changed, 67 insertions, 0 deletions
diff --git a/6.2/tree.c b/6.2/tree.c
new file mode 100644
index 0000000..5e061a4
--- /dev/null
+++ b/6.2/tree.c
@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "tree.h"
+
+struct tnode *naddtree(struct tnode *p, char *w, int bar, int prevmatch)
+{
+	int cond;
+
+	if (p == NULL) {
+		p = talloc();
+		p->word = sneed_strdup(w);
+		p->count = 1;
+		p->match = prevmatch;
+		p->left = p->right = NULL;
+	} else {
+		if ((!strncmp(p->word, w, bar) && strcmp(p->word, w)))
+			p->match = prevmatch = YES;
+
+		if ((cond = strcmp(w, p->word)) == 0) {
+			p->count++;
+		} else if (cond < 0) {
+			p->left = naddtree(p->left, w, bar, prevmatch);
+		} else if (cond > 0) {
+			p->right = naddtree(p->right, w, bar, prevmatch);
+		}
+	}
+
+	return p;
+}
+
+void ntreeprint(struct tnode *p)
+{
+	if (p != NULL) {
+		ntreeprint(p->left);
+		if (p->match)
+			printf("%4d %s\n", p->count, p->word);
+		ntreeprint(p->right);
+	}
+}
+
+void treefree(struct tnode *p) {
+	if (p != NULL) {
+		if (p->left != NULL)
+			treefree(p->left);
+		if (p->right != NULL)
+			treefree(p->right);
+		free(p->word);
+		free(p);
+	}
+}
+
+struct tnode *talloc(void)
+{
+	return (struct tnode *) malloc(sizeof(struct tnode));
+}
+
+char *sneed_strdup(char *s)
+{
+	char *p;
+
+	p = (char *) malloc(strlen(s) + 1);
+	if (p != NULL)
+		strcpy(p, s);
+
+	return p;
+}