二叉树实现，线索二叉树未完成。

Author: gogotanc

BTree/main.c

@@ -0,0 +1,66 @@
+/*
+    该程序实现：
+    输入为：用户用前序遍历法输入一个二叉树，
+    输出为：每个节点位于哪一层。
+*/
+
+
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef char    ElemType;
+
+typedef struct BTreeNode
+{
+    ElemType data;
+    struct BTreeNode *l_child;
+    struct BTreeNode *r_child;
+}Node, *BTree;
+
+void create( BTree *T )
+{
+    char c;
+
+    scanf("%c",&c);
+    if( '*' == c )
+    {
+        (*T) = NULL;
+    }
+    else
+    {
+        (*T) = (Node *)malloc(sizeof(Node));
+        (*T)->data = c;
+        create( &(*T)->l_child );
+        create( &(*T)->r_child );
+    }
+}
+
+void visit( char data, int level )
+{
+    printf("%c 位于第%d层。\n", data, level);
+}
+
+void ProOrderPraverse( BTree T, int level )
+{
+    if( T )
+    {
+        visit( T->data, level );
+        ProOrderPraverse( T->l_child, level+1 );
+        ProOrderPraverse( T->r_child, level+1 );
+    }
+}
+
+int main()
+{
+    printf("请用前序遍历输入二叉树（节点为空请用空格表示）：");
+
+    BTree T = NULL;
+    int level = 1;
+
+    create( &T );
+
+    ProOrderPraverse( T, level );
+
+    return 0;
+}

BTree2/main.c

@@ -0,0 +1,99 @@
+/*
+    线索二叉树
+
+    对空指针部分优化，表示前缀和后继元素
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef char    ElemType;
+
+typedef struct BTreeNode
+{
+    ElemType data;
+    int l_flag;
+    struct BTreeNode *l_child;
+    int r_flag;
+    struct BTreeNode *r_child;
+}Node, *BTree;
+
+//定义全局变量，保存当前遍历的前一个节点
+Node *pre = NULL;
+
+//声明函数
+void create( BTree *T, int *flag );
+void completeTree( BTree T );
+void InOrderTraverse( BTree T );
+
+//主函数
+int main()
+{
+    BTree T = NULL;
+    int flag = 0;
+
+    pre = (Node *)malloc(sizeof(Node));
+
+    create( &T, &flag );
+
+    completeTree( T );
+
+    return 0;
+}
+
+//接收用户的前序遍历输入
+void create( BTree *T, int *flag )
+{
+    ElemType c;
+
+    scanf("%c",&c);
+
+    if( ' ' == c )
+    {
+        *T = NULL;
+        *flag = 1;
+    }
+    else
+    {
+        (*T) = (Node *)malloc(sizeof(Node));
+        (*T)->l_flag = 0;
+        (*T)->r_flag = 0;
+        (*T)->data = c;
+
+        create( &(*T)->l_child, &(*T)->l_flag);
+        create( &(*T)->r_child, &(*T)->r_flag);
+    }
+}
+
+//消除空指针的浪费
+void completeTree( BTree T )
+{
+
+    if( T )
+    {
+        completeTree( T->l_child );
+
+        if( T->l_flag == 1 )
+        {
+            T->l_child = pre;
+        }
+        if( pre->r_flag == 1 )
+        {
+            pre->r_child = T;
+        }
+
+        printf("%c", T->data);
+
+        pre = T;
+
+        completeTree( T->r_child );
+    }
+}
+
+//非递归实现中序遍历
+void InOrderTraverse( BTree T )
+{
+
+}
+
+

task.txt

@@ -7,4 +7,6 @@
 �ߡ���׺����ʽ���׺����ʽ	ok		nifixExpression
 �ˡ��۰���ң��ݹ�ʵ�֣�
 �š�KMP�㷨����ëƬ�㷨��
-ʮ��BF�㷨			ok		BF
+ʮ��BF�㷨			ok		BF
+ʮһ��������ʵ��		ok		BTree
+ʮ��������������ʵ��				BTree2