/*
* The application should be able to calculate factorials, bunny ears, nth number of fibonacci sequence,
* total number of blocks in a triangle, sum of digits (positive number), and occurence of specific
* number (7) in a positive number. I will make a menu to make a selection, and use recursion vs loops.
*/

import java.util.*; import java.util.InputMismatchException;

public class FunWithNumbersTestDrive
{
public static void main(String[] args) { Scanner input = new Scanner(System.in); // Scanner object for user input int choice, userNumber; // Integer for menu selection and another for integer to pass to methods long sevensAbound; // chose a larger primitive type for the howManySevens method to allow for more counting FunWithNumbers fun = new FunWithNumbers(); boolean done = false; try { do { fun.displayMenu(); choice = input.nextInt(); switch(choice) { case 1: System.out.print("Please enter the number that you would like to perform the factorial on: "); userNumber = input.nextInt(); System.out.println("The factoral of " + userNumber + " yields the value: " + fun.findFactorial(userNumber)); break; case 2: System.out.print("Please enter the number of fluffy bunnies whose ears you would like to count: "); userNumber = input.nextInt(); System.out.println(userNumber + " bunnies would get you " + fun.bunnyCounter(userNumber) + " ears."); break; case 3: System.out.print("Please enter the number representing the position in the Fibonacci Sequence " + "that you would like to see the value of: "); userNumber = input.nextInt(); System.out.println("The " + userNumber + " position in the Fibonacci Sequence is the value " + fun.fibonacciSequence(userNumber) + "."); break; case 4: System.out.print("Please enter the number of tiers in the triangle you would like to make: "); userNumber = input.nextInt(); System.out.println("Your triangle of " + userNumber + " height, would have " + fun.makeTriangle(userNumber) + " blocks in it."); break; case 5: System.out.print("Please enter the number whose individual digits you would like to sum: "); userNumber = input.nextInt(); System.out.println("The sum of the individual digits of the number " + userNumber + " is " + fun.addDigits(userNumber)); break; case 6: System.out.print("Plase enter the number that you would like to inspect for occurrences of 7: "); sevensAbound = input.nextLong(); System.out.println("In the number " + sevensAbound + ", there are " + fun.howManySevens(sevensAbound) + " occurrences of the number 7."); break; case 7: done = true; break; default: System.out.println("You have entered an incorrect selection, please try again! (1-7)"); } }while(!done); } catch(InputMismatchException e) { System.out.println("The input given was not numerical, aborting program"); } }
}

class FunWithNumbers
{
public static void displayMenu() { System.out.println("\nPlease make a selection from the following Menu:"); System.out.println("1. Find the factorial of a number."); System.out.println("2. Count the bunny ears of a given number of bunnies."); System.out.println("3. Determine the nth occurrence in the Fibonacci Sequence."); System.out.println("4. Figure the number of blocks to build a triangle of given number height."); System.out.println("5. Find the summation of the individual numbers that comprise a given number."); System.out.println("6. Count the occurrence of the number 7 in a given number."); System.out.println("7. Exit the Program."); } public static int findFactorial(int counter) // Takes in the number to be taken as factorial { if(counter == 1) { return 1; } else { return(counter * (findFactorial(counter - 1))); } } public static int bunnyCounter(int counter)// Takes in the number of bunnies, counts ears { if(counter == 0) { return 0; } else { return (2 + bunnyCounter(counter - 1)); } } public static int fibonacciSequence(int counter) // Delivers nth term of Fibonacci Sequence { if(counter == 0) { return 0; } else if(counter == 1) { return 1; } else { return(fibonacciSequence(counter - 2) + fibonacciSequence(counter - 1)); } } public static int makeTriangle(int counter) // Builds a triangle with base "counter", one less block per line { if(counter == 0) { return 0; } else { return(counter + makeTriangle(counter -1)); } } public static int addDigits(int number) // Sums the individual digits of the number passed { if(number == 0) { return 0; } else { return(number % 10 + addDigits(number / 10)); } } public static long howManySevens(long number) // Counts the occurrences of the number 7 in the given number { if(number == 0) { return 0; } else { long rightMostDigit = (number % 10); if(rightMostDigit == 7) { return(howManySevens(number / 10) + 1); } else { return(howManySevens(number / 10)); } } }
}