Create and traverse a binary tree (forward, middle, and backward). Calculate the number of leaf nodes and the number of nodes.

Binary Tree is one of the most frequently used data structures during the test interview. It mainly includes creating a binary tree by using a program, traversing the binary tree in three order, returning the number of leaf nodes, and finding the total number of Binary Tree nodes. Create a Data Structure of a binary tree node

Typedef struct Node
{
Int data;
Struct Node * left, * right;
} Node; the structure body contains data, left subtree, and sub-tree;

1. The program code for building a binary tree is as follows:

[Cpp] Node * CreatBTree () // create a binary tree
{
Node * t;
Int x;
Scanf ("% d", & x );
If (x = 0)
{
T = NULL;
}
Else
{
T = (Node *) malloc (sizeof (Node ));
T-> data = x;
Printf ("\ n enter the left subnode of the % d node:", t-> data );
T-> left = CreatBTree ();
Printf ("\ n enter the right sub-node of the % d node:", t-> data );
T-> right = CreatBTree ();
}
Return t;
}

Node * CreatBTree () // create a binary tree
{
Node * t;
Int x;
Scanf ("% d", & x );
If (x = 0)
{
T = NULL;
}
Else
{
T = (Node *) malloc (sizeof (Node ));
T-> data = x;
Printf ("\ n enter the left subnode of the % d node:", t-> data );
T-> left = CreatBTree ();
Printf ("\ n enter the right sub-node of the % d node:", t-> data );
T-> right = CreatBTree ();
}
Return t;
}

Ii. Forward traversal of Binary Trees

[Cpp] void preVisit (Node * T)
{
If (T = NULL) return;
Else
{
Printf ("% 3d", T-> data );
PreVisit (T-> left );
PreVisit (T-> right );
}
}

Void preVisit (Node * T)
{
If (T = NULL) return;
Else
{
Printf ("% 3d", T-> data );
PreVisit (T-> left );
PreVisit (T-> right );
}
}
3. Traverse Binary Trees in a central order

[Cpp] void middVisit (Node * T)
{
If (T = NULL) return;
Else
{
MiddVisit (T-> left );
Printf ("% 3d", T-> data );
MiddVisit (T-> right );
}
}

Void middVisit (Node * T)
{
If (T = NULL) return;
Else
{
MiddVisit (T-> left );
Printf ("% 3d", T-> data );
MiddVisit (T-> right );
}
}
Iv. Post-order traversal of Binary Trees

[Cpp] void lastVisit (Node * T)
{
If (T = NULL) return;
Else
{
LastVisit (T-> left );
LastVisit (T-> right );
Printf ("% 3d", T-> data );
}
}

Void lastVisit (Node * T)
{
If (T = NULL) return;
Else
{
LastVisit (T-> left );
LastVisit (T-> right );
Printf ("% 3d", T-> data );
}
}
5. Number of returned leaf nodes

[Cpp] int leafnum (Node * T)
{
If (! T)
{
Return 0;
}
Else if ((! T-> left )&&(! T-> right ))
{
Return 1;
}
Else
{
Return (leafnum (T-> left) + leafnum (T-> right )));
}
}

Int leafnum (Node * T)
{
If (! T)
{
Return 0;
}
Else if ((! T-> left )&&(! T-> right ))
{
Return 1;
}
Else
{
Return (leafnum (T-> left) + leafnum (T-> right )));
}
}
6. Total number of returned nodes

[Cpp] view plaincopyprint? Int Nodenum (Node * T)
{
If (T)
{
Return 1 + Nodenum (T-> left) + Nodenum (T-> right );
}
If (T = NULL)
{
Return 0;
}
 
}

Int Nodenum (Node * T)
{
If (T)
{
Return 1 + Nodenum (T-> left) + Nodenum (T-> right );
}
If (T = NULL)
{
Return 0;
}

}
VII. Test Procedures; [cpp] int menu ();
Void main ()
{
Node * T = NULL;
Int choice;
Do {
Choice = menu ();
If (choice = 1)
{
Printf ("Create a binary tree, input" 0 "to end :! \ N ");
Printf ("Enter the root node: \ n ");
T = CreatBTree ();
Printf ("successful establishment of Binary Tree ");
}
Else if (choice = 2)
{
Printf ("first-order traversal of a binary tree: \ n ");
PreVisit (T );
}
Else if (choice = 3)
{
Printf ("sequential binary tree traversal: \ n ");
MiddVisit (T );
}
Else if (choice = 4)
{
Printf ("suborder traversal of Binary Tree: \ n ");
LastVisit (T );
}
Else if (choice = 5)
{
Int ct = 10;
Ct = leafnum (T );
Printf ("the number of leaf nodes in a binary tree is \ n ");
Printf ("% d \ n", ct );

}
Else if (choice = 7)
{
Int count = Nodenum (T );
Printf ("this binary tree has a total of % d nodes. \ N ", count );
}
Else if (choice = 8)
Exit (0 );
} While (choice <= 8 );
}

Int menu ();
Void main ()
{
Node * T = NULL;
Int choice;
Do {
Choice = menu ();
If (choice = 1)
{
Printf ("Create a binary tree, input" 0 "to end :! \ N ");
Printf ("Enter the root node: \ n ");
T = CreatBTree ();
Printf ("successful establishment of Binary Tree ");
}
Else if (choice = 2)
{
Printf ("first-order traversal of a binary tree: \ n ");
PreVisit (T );
}
Else if (choice = 3)
{
Printf ("sequential binary tree traversal: \ n ");
MiddVisit (T );
}
Else if (choice = 4)
{
Printf ("suborder traversal of Binary Tree: \ n ");
LastVisit (T );
}
Else if (choice = 5)
{
Int ct = 10;
Ct = leafnum (T );
Printf ("the number of leaf nodes in a binary tree is \ n ");
Printf ("% d \ n", ct );

}
Else if (choice = 7)
{
Int count = Nodenum (T );
Printf ("this binary tree has a total of % d nodes. \ N ", count );
}
Else if (choice = 8)
Exit (0 );
} While (choice <= 8 );
}
[Cpp] int menu ()
{
Int choice;
Printf ("\ n ");
Printf ("binary tree \ n ");
Printf ("*************************** \ n ");
Printf ("** \ n ");
Printf ("* Main Menu * \ n ");
Printf ("* 1 create a binary tree * \ n ");
Printf ("* 2 first traverse binary tree * \ n ");
Printf ("* 3 traversing a binary tree in ascending order * \ n ");
Printf ("* 4 suborder traversal of binary tree * \ n ");
Printf ("* 5 binary tree leaf knots * \ n ");
Printf ("* 7 all nodes of a binary tree * \ n ");
Printf ("* 8 Exit Program * \ n ");
Printf ("**************************** \ n ");
Printf ("Enter your options (1, 2, 3, 4, 5, 6, 7, 8): \ n ");
Scanf ("% d", & choice );
Return choice;
}

Int menu ()
{
Int choice;
Printf ("\ n ");
Printf ("binary tree \ n ");
Printf ("*************************** \ n ");
Printf ("** \ n ");
Printf ("* Main Menu * \ n ");
Printf ("* 1 create a binary tree * \ n ");
Printf ("* 2 first traverse binary tree * \ n ");
Printf ("* 3 traversing a binary tree in ascending order * \ n ");
Printf ("* 4 suborder traversal of binary tree * \ n ");
Printf ("* 5 binary tree leaf knots * \ n ");
Printf ("* 7 all nodes of a binary tree * \ n ");
Printf ("* 8 Exit Program * \ n ");
Printf ("**************************** \ n ");
Printf ("Enter your options (1, 2, 3, 4, 5, 6, 7, 8): \ n ");
Scanf ("% d", & choice );
Return choice;
}