From 7e7ddb63cf68d8733a134bfbd22d309c7e152f26 Mon Sep 17 00:00:00 2001
From: Kyle K <kylek389@gmail.com>
Date: Sat, 11 Dec 2010 18:50:00 -0600
Subject: implement prefix, infix, and postfix binary tree print

---
 trees.c | 32 +++++++++++++++++++++++++++-----
 trees.h |  5 +++--
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/trees.c b/trees.c
index dd38e0c..60de45a 100644
--- a/trees.c
+++ b/trees.c
@@ -28,14 +28,36 @@ struct tnode *bintree_insert(struct tnode *p, char *t)
     return p;
 }
 
-/* in-order tree print */
-void treeprint_inorder(struct tnode *p)
+/* CLR: pre-order / prefix tree print */
+void treeprint_prefix(struct tnode *p)
 {
     if (p != NULL)
     {
-        treeprint_inorder(p->left);
         printf("%4d %s\n", p->count, p->text);
-        treeprint_inorder(p->right);
+        treeprint_prefix(p->left);
+        treeprint_prefix(p->right);
+    }
+}
+
+/* LCR: in-order / infix tree print */
+void treeprint_infix(struct tnode *p)
+{
+    if (p != NULL)
+    {
+        treeprint_infix(p->left);
+        printf("%4d %s\n", p->count, p->text);
+        treeprint_infix(p->right);
+    }
+}
+
+/* LRC: post-order / postfix tree print */
+void treeprint_postfix(struct tnode *p)
+{
+    if (p != NULL)
+    {
+        treeprint_postfix(p->left);
+        treeprint_postfix(p->right);
+        printf("%4d %s\n", p->count, p->text);
     }
 }
 
@@ -51,7 +73,7 @@ int main(int argc, char **argv)
     for (i = 0; i < sizeof(tokens) / sizeof(char *); i++)
         root = bintree_insert(root, tokens[i]);
 
-    treeprint_inorder(root);
+    treeprint_infix(root);
 
     return 0;
 }
diff --git a/trees.h b/trees.h
index 93f63d9..95a1c0a 100644
--- a/trees.h
+++ b/trees.h
@@ -16,7 +16,8 @@ struct tnode
 
 /* function prototypes */
 struct tnode *bintree_insert(struct tnode *, char *);
-void treeprint_inorder(struct tnode *);
-
+void treeprint_prefix(struct tnode *);
+void treeprint_infix(struct tnode *);
+void treeprint_postfix(struct tnode *);
 #endif
 
-- 
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