Question

// Group Names:
// Date:
// Program Description:

//   Import required packages
//-->

//   Declare class (SwitchDoLab)
//-->

{

   //   Declare the main method
   //-->

   {

       //   Declare Constant integers SUM = 1, FACTORIAL = 2, QUIT = 3.
       //-->
       //-->
       //-->

       //   Create an integer variable named choice to store user's option.
       //-->

       //   Create a Scanner object

       //   Create a do-while loop that exits only when the user chooses quit (choice = QUIT)
       //   Have the do-statement here

       {
           //   Print the following options:
           //   "This proram does the following:"
           //-->

           //   "1. Sum of numbers from 1 to n"
           //-->

           //   "2. Factorial of n"
           //-->

           //   "3. Quit"
           //-->

           //   "Please choose an option "
           //-->

           //   Read the value the user enters and store it in an integer variable
           //-->
           choice = scan.nextInt();

           //   Create a switch statement with the variable that stores the option as input for the 3 cases

           {
               //add up all the numbers from 1 to the number you entered
               //   case SUM:

                   //   Ask the user to enter a number,

                   // Take user input and put it into the variable
                   //-->
                   int value = scan.nextInt();

                   // Define 2 integer variables, one is to store the summation, the other is to store current number; and initialize them to 0
                   //-->
                   //-->

                   //   Use a while loop to calculate the sum
                   //   Add the while-statement with the condition that variable is less than the number you entered

                   {
                       // increment the current number;

                       // Calculate the summation by adding
                       summation = summation + current;
                   }
                   //   Print the answer saying: 'Sum of numbers from 1 - ' ' is ' '
                   //-->
                   System.out.println("Sum of numbers from 1 - " + value + " is " + summation);

                   //   exit from the switch with a break statement, what happens if you don't use one?
                   break;
               //Calculate the product of all numbers from 1 to the number you entered
               //   case FACTORIAL:
               //-->
               case FACTORIAL:
                   //   Ask the user to enter a number, (if the number is too large, the factorial result will become negative, why?)
                   //-->

                   // Take user input and put it into the variable
                   //-->

                   // Declare an long variable to store current product and initialize it to 1
                   //-->

                   //   Use a for loop to calculate the factorial of n
                   //   Write a for loop with an integer variable and initialize it to the number you entered,
                   // condition that greater than 1, decrement by 1
                   for(int i= value2; > 1 ; )
                   {

                       value3 = value3 * i;
                   }
                   //   Print the answer saying: 'Factorial of ' ' is ' '
                   //-->
                   System.out.println("Factorial of " + value2 + " is " + value3);

                   //   exit from the switch with a break statement.
                   //-->
                   break;

               //   case QUIT:
               //-->

                   //   Print 'Your choice was Quit, Quitting the program, '
                   //-->

                   //   exit from the switch with a break statement
                   //-->

               //   default:
               default:
                   //   Print 'Incorrect choice '<display the incorrect number you entered> ' Please choose again'
                   //-->
                   System.out.println("Incorrect choice " + choice + " Please choose again\n");

                   //   break statement here is optional, why?
                   //-->
                   break;
           //   Close the switch statement
           //-->
           }
       //   Close the do-while loop with a condition that the user's choice is not equal to QUIT
       }while()
   //   Close the main method
   //-->
   }
//Close the Class
//-->

Answer 1

Program:

// Group Names:

// Date:

// Program Description:

// Import required packages

import java.util.Scanner;

// Declare class (SwitchDoLab)

public class SwitchDoLab

{

// Declare the main method

public static void main(String[] args)

{

// Declare Constant integers SUM = 1, FACTORIAL = 2, QUIT = 3.

//-->

final int SUM = 1;

final int FACTORIAL = 2;

final int QUIT = 3;

// Create an integer variable named choice to store user's option.

//-->

int choice;

// Create a Scanner object

//-->

Scanner scan = new Scanner(System.in);

// Create a do-while loop that exits only when the user chooses quit (choice = QUIT)

//-->

do

{

// Print the following options:

// "This program does the following:"

//-->

System.out.println("This program does the following:");

// "1. Sum of numbers from 1 to n"

//-->

System.out.println("1. Sum of numbers from 1 to n");

// "2. Factorial of n"

//-->

System.out.println("2. Factorial of n");

// "3. Quit"

//-->

System.out.println("3. Quit");

// "Please choose an option "

//-->

System.out.print("Please choose an option: ");

// Read the value the user enters and store it in an integer variable

choice = scan.nextInt();

// Create a switch statement with the variable that stores the option as input for the 3 cases

switch(choice)

{

//add up all the numbers from 1 to the number you entered

case SUM:

// Ask the user to enter a number,

System.out.print(" Enter a number: ");

// Take user input and put it into the variable

//-->

int value = scan.nextInt();

// Define 2 integer variables, one is to store the summation, the other is to store current number; and initialize them to 0

//-->

//-->

int summation = 0;

int current = 0;

// Use a while loop to calculate the sum

// Add the while-statement with the condition that variable is less than the number you entered

while(current < value)

{

// increment the current number;

current++;

// Calculate the summation by adding

summation = summation + current;

}

// Print the answer saying: 'Sum of numbers from 1 - ' ' is ' '

//-->

System.out.println("Sum of numbers from 1 - " + value + " is " + summation + " ");

// exit from the switch with a break statement, what happens if you don't use one?

break;

//Calculate the product of all numbers from 1 to the number you entered

// case FACTORIAL:

//-->

case FACTORIAL:

// Ask the user to enter a number, (if the number is too large, the factorial result will become negative, why?)

//-->

System.out.print(" Enter a number: ");

// Take user input and put it into the variable

//-->

int value2;

value2 = scan.nextInt();

// Declare an long variable to store current product and initialize it to 1

//-->

long value3 = 1;

// Use a for loop to calculate the factorial of n

// Write a for loop with an integer variable and initialize it to the number you entered,

// condition that greater than 1, decrement by 1

for(int i = value2; i > 1 ; i--)

{

value3 = value3 * i;

}

// Print the answer saying: 'Factorial of ' ' is ' '

//-->

System.out.println("Factorial of " + value2 + " is " + value3 + " ");

// exit from the switch with a break statement.

//-->

break;

// case QUIT:

//-->

case QUIT:

// Print 'Your choice was Quit, Quitting the program, '

//-->

System.out.println(" Your choice was Quit, Quitting the program");

// exit from the switch with a break statement

//-->

break;

// default:

default:

// Print 'Incorrect choice '<display the incorrect number you entered> ' Please choose again'

//-->

System.out.println(" Incorrect choice " + choice + " Please choose again ");

// break statement here is optional, why?

//-->

break;

// Close the switch statement

//-->

}

// Close the do-while loop with a condition that the user's choice is not equal to QUIT

}while(choice != QUIT);

// Close the main method

//-->

}

//Close the Class

//-->

}

Output:

Program Screenshot: