Question

1) Create a main() method with a switch statement that calls either a sum() OR factorial() method, depending on what selection the user of the program makes - ask the user to enter a selection (with System.out.println()), create a Scanner then read the user's input with a call to Scanner next(), then call the appropriate method in a switch (the String that was read from the call to Scanner.next() should be what you use as your switch condition).

2) Create a method, sum(), to include a FOR loop that will :

Get a scanner and input a number from the keyboard in main(). The method will take one parameter and calculate the sum up to that number. For example, if you pass 5, it it will calculate 1+2+3+4+5 and will return it back to main() method.

3) Create another method, factorial(), and repeat what was done for the sum() method above but compute the product instead.

in JAVA please!

Answer 1

Program:

import java.util.Scanner;

public class Main

{

public static void main(String[] args)

{

int number; // variable declaration

String selection; // variable declaration

Scanner scan = new Scanner(System.in); // scanner declaration

System.out.println("Enter sum to perform sum operation\nEnter factorial to perform factorial operation");

System.out.print("Enter your choice: ");

selection = scan.next(); // Accept the user choice

switch(selection.toLowerCase()) // switch case

{

case "sum": // If user enter sum

System.out.print("\nEnter a number: ");

number = scan.nextInt(); // Accept the number to calculate the sum

System.out.println("The sum of is numbers is "+ sum(number)); // calling function and print the result

break;

case "factorial":

System.out.print("\nEnter a number: ");

number = scan.nextInt(); // Accept the number to calculate the sum

System.out.println("The factorial of numbers is " + factorial(number)); // calling function and print the result

break;

default:

System.out.println("\nInvalid choice.\n");

}

}

public static int sum(int number) // called function to perform the sum

{

int sumNumbers = 0; // variable declaration

for(int i = 1; i <= number; i++)

{

sumNumbers = sumNumbers + i; // calculate the sum of numbers

}

return sumNumbers; // return the sum

}

public static int factorial(int number) // called function to find the factorial

{

int factorialNumbers = 1; // Initially factorial is 1

for(int i = 1; i <= number; i++) // calculate the factorial

{

factorialNumbers = factorialNumbers * i; // calculate the factorial of numbers

}

return factorialNumbers; // return the factorial of nubers

}

}

Output: