BSTDeletion_CPP.cpp

/* Deleting a node from Binary search tree */
#include<iostream>
using namespace std;
struct Node {
	int data;
	struct Node *left;
	struct Node *right;
};
//Function to find minimum in a tree. 
Node* FindMin(Node* root)
{
	while(root->left != NULL) root = root->left;
	return root;
}

// Function to search a delete a value from tree.
struct Node* Delete(struct Node *root, int data) {
	if(root == NULL) return root; 
	else if(data < root->data) root->left = Delete(root->left,data);
	else if (data > root->data) root->right = Delete(root->right,data);
	// Wohoo... I found you, Get ready to be deleted	
	else {
		// Case 1:  No child
		if(root->left == NULL && root->right == NULL) { 
			delete root;
			root = NULL;
		}
		//Case 2: One child 
		else if(root->left == NULL) {
			struct Node *temp = root;
			root = root->right;
			delete temp;
		}
		else if(root->right == NULL) {
			struct Node *temp = root;
			root = root->left;
			delete temp;
		}
		// case 3: 2 children
		else { 
			struct Node *temp = FindMin(root->right);
			root->data = temp->data;
			root->right = Delete(root->right,temp->data);
		}
	}
	return root;
}
 
//Function to visit nodes in Inorder
void Inorder(Node *root) {
	if(root == NULL) return;
 
	Inorder(root->left);       //Visit left subtree
	printf("%d ",root->data);  //Print data
	Inorder(root->right);      // Visit right subtree
}
 
// Function to Insert Node in a Binary Search Tree
Node* Insert(Node *root,char data) {
	if(root == NULL) {
		root = new Node();
		root->data = data;
		root->left = root->right = NULL;
	}
	else if(data <= root->data)
		root->left = Insert(root->left,data);
	else 
		root->right = Insert(root->right,data);
	return root;
}

int main() {
	/*Code To Test the logic
	  Creating an example tree
	                    5
			   / \
			  3   10
			 / \   \
			1   4   11
    */
	Node* root = NULL;
	root = Insert(root,5); root = Insert(root,10);
	root = Insert(root,3); root = Insert(root,4); 
	root = Insert(root,1); root = Insert(root,11);

	// Deleting node with value 5, change this value to test other cases
	root = Delete(root,5);

	//Print Nodes in Inorder
	cout<<"Inorder: ";
	Inorder(root);
	cout<<"\n";
}

I have a doubt.. how the ctrl trasnfers to else if to else

If all the statements in the "if" conditions (including "else if") are false, then it will by default execute the "else" statement.