In C# 6.1 Write a program to store and display a tree. You may limit the type of
ID: 3827036 • Letter: I
Question
In C#
6.1 Write a program to store and display a tree. You may limit the type of trees that it will process, e.g. complete binary trees, or heaps. You may choose the data structures to store and process the tree, e.g. an array. In your test program, be sure to print the node values in tree “format”.
6.2 Write a function to add an element to an existing tree.
6.3 Write a function to delete an element from an existing tree.
6.4 Write a function to perform an “in-order” traversal on an existing tree.
6.5 Write a function to perform an “pre-order” traversal on an existing tree.
6.6 Write a function to perform an “post-order” traversal on an existing tree. 6.7 Write a function to perform an “level-order” traversal on an existing tree.
6.8 Write a function to find the children of a specified node. 6.9 Write a function to find the parent of a specified node.
Explanation / Answer
#include <iostream>
using namespace std;
// Node class
class Node {
int key;
Node* left;
Node* right;
public:
Node() { key=-1; left=NULL; right=NULL; };
void setKey(int aKey) { key = aKey; };
void setLeft(Node* aLeft) { left = aLeft; };
void setRight(Node* aRight) { right = aRight; };
int Key() { return key; };
Node* Left() { return left; };
Node* Right() { return right; };
};
// Tree class
class Tree {
Node* root;
public:
Tree();
~Tree();
Node* Root() { return root; };
void addNode(int key);
void inOrder(Node* n);
void preOrder(Node* n);
void postOrder(Node* n);
private:
void addNode(int key, Node* leaf);
void freeNode(Node* leaf);
};
// Constructor
Tree::Tree() {
root = NULL;
}
// Destructor
Tree::~Tree() {
freeNode(root);
}
// Free the node
void Tree::freeNode(Node* leaf)
{
if ( leaf != NULL )
{
freeNode(leaf->Left());
freeNode(leaf->Right());
delete leaf;
}
}
// Add a node
void Tree::addNode(int key) {
// No elements. Add the root
if ( root == NULL ) {
cout << "add root node ... " << key << endl;
Node* n = new Node();
n->setKey(key);
root = n;
}
else {
cout << "add other node ... " << key << endl;
addNode(key, root);
}
}
// Add a node (private)
void Tree::addNode(int key, Node* leaf) {
if ( key <= leaf->Key() ) {
if ( leaf->Left() != NULL )
addNode(key, leaf->Left());
else {
Node* n = new Node();
n->setKey(key);
leaf->setLeft(n);
}
}
else {
if ( leaf->Right() != NULL )
addNode(key, leaf->Right());
else {
Node* n = new Node();
n->setKey(key);
leaf->setRight(n);
}
}
}
// Print the tree in-order
// Traverse the left sub-tree, root, right sub-tree
void Tree::inOrder(Node* n) {
if ( n ) {
inOrder(n->Left());
cout << n->Key() << " ";
inOrder(n->Right());
}
}
// Print the tree pre-order
// Traverse the root, left sub-tree, right sub-tree
void Tree::preOrder(Node* n) {
if ( n ) {
cout << n->Key() << " ";
preOrder(n->Left());
preOrder(n->Right());
}
}
// Print the tree post-order
// Traverse left sub-tree, right sub-tree, root
void Tree::postOrder(Node* n) {
if ( n ) {
postOrder(n->Left());
postOrder(n->Right());
cout << n->Key() << " ";
}
}
// Test main program
int main() {
Tree* tree = new Tree();
tree->addNode(30);
tree->addNode(10);
tree->addNode(20);
tree->addNode(40);
tree->addNode(50);
cout << "In order traversal" << endl;
tree->inOrder(tree->Root());
cout << endl;
cout << "Pre order traversal" << endl;
tree->preOrder(tree->Root());
cout << endl;
cout << "Post order traversal" << endl;
tree->postOrder(tree->Root());
cout << endl;
delete tree;
return 0;
}