Question

1. In this programming assignment, you are asked to write a multi-threaded program using JAVA to compute the sum of an arithmetic series from 1 to 200 using pthreads.   The main thread is responsible for creating two child threads

2. The first child thread should compute the partial sum of the series from 1 to 100 and the second computes the partial sum of another series from 101 to 200.

3. The main thread should accumulate the partial sums computed by the child threads to obtain the final sum and then print out the results, including the partial sums computed by each child thread and the final sum accumulated by the main thread.

Answer 1

// ArithmeticSeries class that implements Runnable interface
// and calculate sum from start to end by taking parameters through constructor
class ArithmeticSeries implements Runnable{
private volatile int sum = 0;
private int start, end;
// get start and end
public ArithmeticSeries(int s, int e){
    start = s;
    end = e;
}

// get sum
@Override
public void run() {
    calculateSum();
}

// calculate sum by looping from start to end and adding it to sum
public void calculateSum() {
    try{
      for(int i = start; i <= end; i++){
        sum = sum + i;
      }
    }catch (Exception e){
    }
}

// return calculated result sum
public int getSum(){
    return sum;
}
}

public class ArithmeticSeriesTest{
public static void main(String args[]){
    // create two ArithmeticSeries object by passing 1-100 & 101-200 to each object
    ArithmeticSeries as1 = new ArithmeticSeries(1, 100);
    ArithmeticSeries as2 = new ArithmeticSeries(101, 200);

    // create two threads from main thread by passing ArithmeticSeries object
    Thread t1 = new Thread(as1);
    Thread t2 = new Thread(as2);
    // start executing threads
    t1.start();
    t2.start();

    // join threads so that each thread can report main thread about exit
    try{
      t1.join();
      t2.join();
    }catch(Exception e){}

    // collect result from both threads and compute final sum
    int as1_sum = as1.getSum();
    int as2_sum = as2.getSum();
    int total = as1_sum + as2_sum;
    System.out.println("sum:- " + total);

}
}