tree data structure

1class TreeNode:
2    def __init__(self, data):
3        self.data = data
4        self.children = []
5        self.parent = None
6
7    def add_child(self, child):
8        child.parent = self
9        self.children.append(child)
10
11    def getlevel(self):
12        level = 0
13        p = self.parent
14        while p:
15            level += 1
16            p = p.parent
17        return level
18
19    def printt(self):
20        prefix = (" " * 4 * self.getlevel()) + ("|--" if self.parent else "")
21        print(prefix + self.data)
22        if self.children:
23            for child in self.children:
24                child.printt()
25
26
27def build_tree():
28    root = TreeNode("Food")
29
30    italy = TreeNode("Italy")
31    italy.add_child(TreeNode("Pizza"))
32    italy.add_child(TreeNode("Lasgna"))
33    italy.add_child(TreeNode("Pistacho Ice"))
34
35    chinese = TreeNode("Chineese")
36    chinese.add_child(TreeNode("Noodles"))
37    chinese.add_child(TreeNode("Rice balls"))
38    chinese.add_child(TreeNode("Fried Rice"))
39
40    mexican = TreeNode("Mexican")
41    mexican.add_child(TreeNode('Tacos'))
42    mexican.add_child(TreeNode('Gyro'))
43    mexican.add_child(TreeNode('Shawarma'))
44
45    root.add_child(italy)
46    root.add_child(chinese)
47    root.add_child(mexican)
48
49    return root
50
51    # mexican.printt()
52
53
54if __name__ == "__main__":
55    root = build_tree()
56    root.printt()
57

1struct node {
2   int data;   
3   struct node *leftChild;
4   struct node *rightChild;
5};

1void insert(int data) {
2   struct node *tempNode = (struct node*) malloc(sizeof(struct node));
3   struct node *current;
4   struct node *parent;
5
6   tempNode->data = data;
7   tempNode->leftChild = NULL;
8   tempNode->rightChild = NULL;
9
10   //if tree is empty, create root node
11   if(root == NULL) {
12      root = tempNode;
13   } else {
14      current = root;
15      parent  = NULL;
16
17      while(1) {                
18         parent = current;
19
20         //go to left of the tree
21         if(data < parent->data) {
22            current = current->leftChild;                
23            
24            //insert to the left
25            if(current == NULL) {
26               parent->leftChild = tempNode;
27               return;
28            }
29         }
30			
31         //go to right of the tree
32         else {
33            current = current->rightChild;
34            
35            //insert to the right
36            if(current == NULL) {
37               parent->rightChild = tempNode;
38               return;
39            }
40         }
41      }            
42   }
43}

1If root is NULL 
2   then create root node
3return
4
5If root exists then
6   compare the data with node.data
7   
8   while until insertion position is located
9
10      If data is greater than node.data
11         goto right subtree
12      else
13         goto left subtree
14
15   endwhile 
16   
17   insert data
18	
19end If      

1// Tree traversal in C
2
3#include <stdio.h>
4#include <stdlib.h>
5
6struct node {
7  int item;
8  struct node* left;
9  struct node* right;
10};
11
12// Inorder traversal
13void inorderTraversal(struct node* root) {
14  if (root == NULL) return;
15  inorderTraversal(root->left);
16  printf("%d ->", root->item);
17  inorderTraversal(root->right);
18}
19
20// preorderTraversal traversal
21void preorderTraversal(struct node* root) {
22  if (root == NULL) return;
23  printf("%d ->", root->item);
24  preorderTraversal(root->left);
25  preorderTraversal(root->right);
26}
27
28// postorderTraversal traversal
29void postorderTraversal(struct node* root) {
30  if (root == NULL) return;
31  postorderTraversal(root->left);
32  postorderTraversal(root->right);
33  printf("%d ->", root->item);
34}
35
36// Create a new Node
37struct node* createNode(value) {
38  struct node* newNode = malloc(sizeof(struct node));
39  newNode->item = value;
40  newNode->left = NULL;
41  newNode->right = NULL;
42
43  return newNode;
44}
45
46// Insert on the left of the node
47struct node* insertLeft(struct node* root, int value) {
48  root->left = createNode(value);
49  return root->left;
50}
51
52// Insert on the right of the node
53struct node* insertRight(struct node* root, int value) {
54  root->right = createNode(value);
55  return root->right;
56}
57
58int main() {
59  struct node* root = createNode(1);
60  insertLeft(root, 12);
61  insertRight(root, 9);
62
63  insertLeft(root->left, 5);
64  insertRight(root->left, 6);
65
66  printf("Inorder traversal \n");
67  inorderTraversal(root);
68
69  printf("\nPreorder traversal \n");
70  preorderTraversal(root);
71
72  printf("\nPostorder traversal \n");
73  postorderTraversal(root);
74}