c/c++面试39-44之内存动态分配

 1 #include <stdio.h> 
 2 #include <stdlib.h> 
 3  
 4 struct Tag_Node 
 5 { 
 6     struct Tag_Node *left; 
 7     struct Tag_Node *right; 
 8     int value; 
 9 }; 
10 typedef struct Tag_Node TNode; 
11  
12 TNode* root = NULL; 
13  
14 void append(int N); 
15 void print(); 
16  
17 int main() 
18 { 
19     append(63); 
20     append(45); 
21     append(32); 
22     append(77); 
23     append(96); 
24     append(21); 
25     append(17); 
26     printf("head:%d\n", root->value); 
27     print(); 
28     getchar(); 
29 } 
30  
31 void append(int N) 
32 { 
33     TNode *NewNode = (TNode *)malloc(sizeof(TNode)); 
34     NewNode->value = N; 
35     NewNode->left = NULL;//初始化这里很重要 
36     NewNode->right = NULL; 
37  
38     if (root == NULL) 
39     { 
40         root = NewNode;//就指向根节点 
41         return; 
42     } 
43     else 
44     { 
45         TNode *temp =  NULL; 
46         temp = root; 
47         while ((N >= temp->value&&temp->left != NULL)||(N<temp->value&&temp->right!=NULL)) 
48         { 
49             while (N >= temp->value&&temp->left != NULL) 
50             { 
51                 temp = temp->left; 
52             } 
53             while (N <= temp->value&&temp->right != NULL) 
54             { 
55                 temp = temp->right; 
56             } 
57         } 
58         if (N >= temp->value) 
59         { 
60             temp->left = NewNode; 
61             NewNode->right = temp;//形成双向链表 
62         } 
63         else 
64         { 
65             temp->right = NewNode; 
66             NewNode->left = temp; 
67         } 
68         return; 
69          
70     } 
71 } 
72  
73 void print() 
74 { 
75     TNode* leftside = NULL; 
76  
77     if (root == NULL) 
78     { 
79         printf("there is not any element"); 
80         return; 
81     } 
82     leftside = root->left; 
83  
84     while (1) 
85     { 
86         if (leftside->left == NULL) 
87         { 
88             break; 
89         } 
90         leftside = leftside->left; 
91     } 
92     while (leftside != NULL) 
93     { 
94         printf("%d ", leftside->value); 
95         leftside = leftside->right; 
96     } 
97 }