BMain.java

/* 	This is the main Class for B-Tree implementation in Java.
 *	It creates a B-Tree Tree with order user value N.
 *	Then Lets the user do the following operations on the BTree Tree
 *		1.Add more Keys to the Tree.
 *		2.Print the entire Tree in preorder.
 *		3.Delete a key from the leaf
 *		4.Search for a Key and print the Node it belongs to
 *	The above menu is put in a while loop so that the User has a easy interface to Test or familiarize with the B-Tree.
 *
 * Authors: Jeremy Phelps and Krish Unnikannan
 */
import java.util.Scanner;
public class BMain 
{

	public static void main(String[] args)
	{
        Scanner input = new Scanner( System.in );
		int n,n2,temp;
		System.out.print("Enter the t of the Tree?  ");
		n=input.nextInt();
		
        while ( n<2)
		{	
            System.out.print("Please enter a integer greater than 1 : ");
			n=input.nextInt();//  User inputs the order of Tree and is assinged to N.
		}
		BTree tree = new BTree(n);//  B-Tree Tree with order  N is created.

        // Initial Values are added to the Tree.. The user and Input any number of Values.
		System.out.print("\n How many values do you want to enter?:  ");	
        n2 = input.nextInt();

        for ( int i=0;i< n2;i++)
		{
            System.out.print("\nEnter Value:");
			System.out.println(i+1);
			temp=input.nextInt();
			tree.insert(tree,temp);
		}
		int choice,k;// Variables used to control the Repeated loop of the MENU.

        boolean flag;
		flag=true;
			System.out.println("\tM\tE\tN\tU\n");
			System.out.println("1. Enter more values in a Tree");
			System.out.println("2. Print the whole  Tree in preorder");
			System.out.println("3. Search for a Key and print the Node it belongs to");
			System.out.println("4. Delete a key from the leaf");
			System.out.println("5. Exit");

		while (flag)// This While loop runs as long as the user enters anything other than a 5.
		{


			System.out.print("\nPlease enter your choice::");
			choice=input.nextInt();
			if ( choice == 5)
			{		
                System.out.printf("The program is exiting...,\n"
                                  +"Thank you for using B-Tree implementation in Java\n"
                                  +" Authors: Jeremy Phelps and Krish Unnikannan");
			    System.exit(0);
				flag=false;
				break;
			}
		
            else
			{
			 	switch(choice)
			 	{
			 		case 1: //If the User Enters 1 this case is executed and 
                            //its function is to Enter more values in a Tree.
	
                        System.out.print("How many values do you want to enter?:");
						n2=input.nextInt();

                        for ( int i=0;i< n2;i++)
						{
                            System.out.print("\nEnter Value: ");
							System.out.println(i+1);
							temp=input.nextInt();
							tree.insert(tree,temp);
                        }
                        break;

					case 2: //If the User Enters 2 this case is executed and 
                            //its function is to Print the whole  Tree in preorder format.
						
                        tree.print(tree.root);
						System.out.println();
						break;

					case 3: //If the User Enters 3 this case is executed and 
                            //its function is to Delete a key from the leaf
		
                        System.out.println("What is the key you wish to search for:");
						int key2=input.nextInt();
						tree.SearchPrintNode(tree,key2);

						break;
					case 4: //If User Enters 4, this case is executed 
                            //Its Function is to search for a Key and print the Node it belongs to
						
                        System.out.println("Enter a key to be deleted:");
						int key=input.nextInt();
						tree.deleteKey(tree,key);
						System.out.println("Here is the tree printed in preorder after delete");
						tree.print(tree.root);
						break;

					case 5: //If the User Enters 5, this case is executed and 
                            //its function is to Exit
			
                        System.exit(0);
						break;

						default: // If the User enters a wrong choice, then this case is executed.
						System.out.println("\nPlease enter a valid choice of 1,2,3 or 4\n");
						break;
	 			}//end of switch block
			 }//end of else block
		}//end while(flag)
	}//main
}//class