Question

Write an application that uses multithreading to compute the sum of the integers in an array of size 100,000. You can populate the array with random numbers and your application should display the sum. (JAVA)

Answer 1

Program Screenshots:

Sample Output:

Code to be Copied:

DriverProgram.java

//import required package
import java.util.Random;

// Application driver code to compute sum
public class DriverProgram
{
   //declare local variable
   public static final int SIZE = 100000;

   //main method
   public static void main(String[] args)
   {
       //create object for random
       Random r = new Random();
       //create array of size
       int[] array = new int[SIZE];
       //use for loop to create random numbers
       for (int i = 0; i < array.length; i++)
       {
           array[i] = r.nextInt(100001) + 1;
       }      
       //call the method in the mutithread class
       long arraySum= MultiThreading.multiThreadSum(array);
       //print the result
       System.out.println("Array sum using MultiThreading is: " + arraySum);
   }
}

MultiThreading.java

//Create class Application which extends thread
public class MultiThreading extends Thread
{
   //Declare 8 threads
   public static final int NUM_THREADS = 10;
   private int[] array;
   private int start, end, sum;

   //create constructor for the class
   public MultiThreading(int[] inputarr, int l, int h)
   {
       this.array = inputarr;
       this.start = l;
       this.end = Math.min(h, inputarr.length);
   }

   //implement run method
   //to invoke when thread starts
   public void run()
   {
       //call the other method to compute the sum
       //for each thred
       sum = eachThreadSum(array, start, end);
   }

   //Implement method sum to compute eachThreadSum
   public static int eachThreadSum(int[] arr, int low, int high)
   {
       //declare variable
       int total = 0;
       //use for-loop to compute the total
       for (int i = low; i < high; i++)
       {
           total += arr[i];
       }
       //return total
       return total;
   }
   //implement method to compute sum for multithreads
   public static int multiThreadSum(int[] arr)
   {
       //call sub method for the array and numthreads
       return multiThreadSum(arr, NUM_THREADS);
   }

   //implement method to compute sum
   public static int multiThreadSum (int[] arr, int threads)
   {
       //get the size of the array of each thread
       int size = (int) Math.ceil(arr.length * 1.0 / threads);
      
       MultiThreading[] threadSum = new MultiThreading[threads];

       //use for-loop to compute sum
       for (int i = 0; i < threads; i++)
       {
           threadSum[i] = new MultiThreading(arr, i * size, (i + 1) * size);
           //invoke start method to implement run method
           threadSum[i].start();
       }

       //join each thread
       try
       {
           for (MultiThreading sum : threadSum)
           {
               sum.join();
           }
       }
       //if the sum is not calculated
       //throw exception contains message
       catch (InterruptedException e)
       {
           e.getMessage();
       }
       //compute sum by calling method
       int total = 0;
       for (MultiThreading sum : threadSum)
       {
           total += sum.getPartialSum();
       }
       //return total
       return total;
   }
   //accessor method
   public int getPartialSum()
   {
       return sum;
   }
}