Question

In this lab, you will create one class named ArrayFun.java which will contain a main method and 4 static methods that will be called from the main method. The process for your main method will be as follows: Declare and create a Scanner object to read from the keyboard Declare and create an array that will hold up to 100 integers Declare a variable to keep track of the number of integers currently in the array Call the fillArray method described below, passing the appropriate arguments and storing the result in the appropriate variable. Call the compute Product method described below, passing the appropriate arguments, and print the result to the screen with an appropriate label Ask the user for an integer and store in a variable named factor Use the countMultiples method described below to compute the number of multiples of that factor and print the result with an appropriate label Use the printArray method to print out the values in the array fillArray The static fillArray method will accept two parameters: an integer array and a Scanner. It must ask the user for values to add to the array, beginning at index 0, stopping when the user enters -999. Make sure that the-999 is not included in the array. The method will return the number of values put into the array, computeProduct The statie compute Product method will accept two parameters: an integer array and an integer representing the number of valid values in the array. The method will return the product of the integers in the array. Note: test this with relatively small values or short arrays.

Answer 1

Program:

import java.util.Scanner;

public class ArrayFun {

   public static void main(String[] args) {
       //create an object to Scanner class to read input from the keyboard
       Scanner input = new Scanner(System.in);
       //create an array that can hold 100 values
       int[] arr = new int[100];
       //fill the array using fillArray method and get the number of values in the array
       int actualSize = fillArray(arr, input);
       //print the array
       printArray(arr, actualSize);
       //print the product of array elements using computeProduct method
       System.out.println("The product of array elements: " + computProduct(arr, actualSize));
       //ask the user for and integer for factor
       System.out.print("Enter an integer for factor: ");
       int factor = input.nextInt();
       //get the number of multiples of factor
       System.out.println("The number of multiples of " + factor + ": " + countMultiples(arr, actualSize, factor));
       input.close();
   }

   //method that fills the array
   public static int fillArray(int[] arr, Scanner input)
   {
       boolean repeat = true;
       int value, size = 0;
       //run a loop to until -999 is entered
       while(repeat)
       {
           //prompt and read a number
           System.out.print("Enter a value into the array (-999 to stop entering): ");
           value = input.nextInt();
           //if -999 is entered set repeat to false to terminate the loop
           if(value == -999)
               repeat = false;
           //else store the value entered in the array and increment the size
           else
           {
               arr[size] = value;
               size++;
           }
       }
       //return the number of values in the array
       return size;
   }

   //method that computes the product of elements in the array
   public static int computProduct(int[] arr, int size)
   {
       int product = 1;
       //run a loop to iterate through the array
       for(int i = 0; i < size; i++)
       {
           //multiple product by arr[i];
           product = product * arr[i];
       }
       return product; //return the product of the elements in the array
   }

   //method that counts the number of multiples of factor given
   public static int countMultiples(int[] arr, int size, int factor)
   {
       int count = 0;
       //run a loop to iterate through the array
       for(int i = 0; i < size; i++)
       {
           //check if the array element is a multiple of factor
           if(arr[i] % factor == 0)
               count++;
       }
       return count;
   }

   //method that prints the array
   public static void printArray(int[] arr, int size)
   {
       System.out.println("The values in the array are: ");
       //run a loop to iterate through the array
       for(int i = 0; i < size; i++)
       {
           //print the array values one per line
           System.out.println(arr[i]);
       }
   }
}

Output:

Console 3 <terminated> ArrayFun [Java Application] C\Program Files\Java\jre1.8.0 151\bin\javaw.exe (Nov 7, 2019, 8:57:05 AM) Enter a value into the array (-999 to stop entering): 2 Enter a value into the array (-999 to stop entering): 4 Enter a value into the array (-999 to stop entering): 5 Enter a value into the array (-999 to stop entering): 7 Enter a value into the array (-999 to stop entering): 10 Enter a value into the array 999 to stop entering): 25 Enter a value into the array (-999 to stop entering): 35 Enter a value into the array (-999 to stop entering): -999 The values in the array are 2 4 7 10 25 35 The product of array elements: 2450000 Enter an integer for factor: 2 The number of multiples of 2: 3

Program Screenshot:

ArrayFun.java 1 import java.util.Scanner; 3 public class ArrayFun public static void main(String [] args) //create an object to Scanner class to read input from the keyboard Scanner input = new Scanner(System. in) //create an array that can hold 100 values int [] arr = new int[100]; //fill the array using fillArray method and get the number of values in the array int actualsize = filLArray(arr, input) //print the array printArray(arr, actualsize) //print the product of array elements using computeProduct method System.out.println ("The product of array elements: "+ computProduct (arr, actualSize) ); 1ask the usser for and integer for factor System.out.print("Enter an integer for factor: "); int factor = input.nextInt() 50 7 10 11 12 13 14 15 16 17 18 /get the number of multiples of factor System.out.println("The number of multiples of " + factor + ": " + countMultiples (arr, actualSize, factor)); input.close); } 19 20 21 22 23

ArrayFun.java 23 //method that fills the array 24 public static int fillArray (int [] arr, Scanner input) 25e 26 boolean repeat true; int value, size = 0; //run a loop to until -999 is entered 27 28 29 while(repeat) 30 31 //prompt and read a number System.out.print("Enter a value into the array (-999 to stop entering): "); value input.nextInt); 1/if -999 is entered set repeat to false to terminate the loop if (value -999) repeat false; //else store the value entered in the array and increment the size 32 33 34 35 36 37 38 else 39 { arr[size] value; size++ } } //return the number of values in the array return size; 40 41 42 43 44 45 46 } 47 48 49 50e 51 52 53 54 55 56 57 58 59 60 //method that computes the product of elements in the array public static int computProduct (int [] arr, int size) = 1; int product /run a loop to iterate through the array for (int i 0; i < size; it+ { //multiple product by arcli] product product arr[i]; } return product; //return the product of the elements in the array } ) 61

61 //method that counts the number of multiples of factor given public static int countMultiples (int [] arr, int size, int factor) 62 63e 64 int count= 0; //run a loop to iterate through the array for (int i= 0; i < size; i++ { //check if the array element is a multiple of factor if (arr[i] factor == 0) 65 66 67 68 69 70 count++ 71 } return count; 72 73 } 74 75 //method that prints the array 76 public static void printArray (int [] arr, int size) 77e 78 79 System.out.println("The values in the array are: "); //run a loop to iterate through the array for(int i 0; i < size; i++ 80 81 82 83 84 //print the array values one per 1line System.out.println (arr[i]); 85 } 86 87