Two thread print natural number

Print natural numbers 1 to 100 using two threads

 Print natural numbers 1 to 100 using two threads without using wait or synchronized where one thread prints only odd number and other thread prints only even number ?
Solution :

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

package com.ai1tutorial.java.multi.threading; class OddPrint implements Runnable { static boolean flag = true; public void run() { for (int i = 1; i <= 99;) { if (flag) { System.out.print(i+"\t"); flag = false; i = i + 2; } } } } class EvenPrint implements Runnable { public void run() { for (int i = 2; i <= 100;) { if (!OddPrint.flag) { System.out.print(i+"\t"); OddPrint.flag = true; i = i + 2; } } } } public class NaturalNumber { public static void main(String[] args) { new Thread(new OddPrint()).start(); new Thread(new EvenPrint()).start(); } }

Output::

1	1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

5. Print natural numbers 1 to 100 using two threads using wait or synchronized where one thread prints only odd number and other thread prints only even number?
Solution :

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71

package com.ai1tutorial.java.multi.threading; class OddPrint implements Runnable { static boolean flag = true; private Object lock = null; public OddPrint(Object lock) { this.lock = lock; } public void run() { for (int i = 1; i <= 99; i = i + 2) { synchronized (lock) { while (!flag) { try { lock.wait(); } catch (InterruptedException e) { System.out.println("Error in Thread 1: " + e.getMessage()); } } System.out.println("Thread 1: " + i); flag = false; lock.notifyAll(); } } } } class EvenPrint implements Runnable { private Object lock = null; public EvenPrint(Object lock) { this.lock = lock; } public void run() { for (int i = 2; i <= 100; i = i + 2) { synchronized (lock) { while (OddPrint.flag) { try { lock.wait(); } catch (InterruptedException e) { System.out.println("Error in Thread 2: " + e.getMessage()); } } System.out.println("Thread 2: " + i); OddPrint.flag = true; lock.notifyAll(); } } } } public class NaturalNumberMultiThread { private static Object lock = new Object(); public static void main(String[] args) { new Thread(new OddPrint(lock)).start(); new Thread(new EvenPrint(lock)).start(); } }

Output::

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

Thread 1: 1 Thread 2: 2 Thread 1: 3 Thread 2: 4 Thread 1: 5 Thread 2: 6 Thread 1: 7 Thread 2: 8 Thread 1: 9 Thread 2: 10 Thread 1: 11 Thread 2: 12 Thread 1: 13 Thread 2: 14 Thread 1: 15 Thread 2: 16 Thread 1: 17 Thread 2: 18 Thread 1: 19 Thread 2: 20 Thread 1: 21 Thread 2: 22 Thread 1: 23 Thread 2: 24 Thread 1: 25 Thread 2: 26 Thread 1: 27 Thread 2: 28 Thread 1: 29 Thread 2: 30 Thread 1: 31 Thread 2: 32 Thread 1: 33 Thread 2: 34 Thread 1: 35 Thread 2: 36 Thread 1: 37 Thread 2: 38 Thread 1: 39 Thread 2: 40 Thread 1: 41 Thread 2: 42 Thread 1: 43 Thread 2: 44 Thread 1: 45 Thread 2: 46 Thread 1: 47 Thread 2: 48 Thread 1: 49 Thread 2: 50 Thread 1: 51 Thread 2: 52 Thread 1: 53 Thread 2: 54 Thread 1: 55 Thread 2: 56 Thread 1: 57 Thread 2: 58 Thread 1: 59 Thread 2: 60 Thread 1: 61 Thread 2: 62 Thread 1: 63 Thread 2: 64 Thread 1: 65 Thread 2: 66 Thread 1: 67 Thread 2: 68 Thread 1: 69 Thread 2: 70 Thread 1: 71 Thread 2: 72 Thread 1: 73 Thread 2: 74 Thread 1: 75 Thread 2: 76 Thread 1: 77 Thread 2: 78 Thread 1: 79 Thread 2: 80 Thread 1: 81 Thread 2: 82 Thread 1: 83 Thread 2: 84 Thread 1: 85 Thread 2: 86 Thread 1: 87 Thread 2: 88 Thread 1: 89 Thread 2: 90 Thread 1: 91 Thread 2: 92 Thread 1: 93 Thread 2: 94 Thread 1: 95 Thread 2: 96 Thread 1: 97 Thread 2: 98 Thread 1: 99 Thread 2: 100

package com.mandal.org.thread;

public class MultipleThreadSequenceWisePrint {
 private volatile Integer count = 1;
    private volatile Integer threadIdToRun = 1;
    private Object object = new Object();

    public static void main(String[] args) {

     MultipleThreadSequenceWisePrint testClass = new MultipleThreadSequenceWisePrint();
        Thread t1 = new Thread(testClass.new Printer(1));
        Thread t2 = new Thread(testClass.new Printer(2));
        Thread t3 = new Thread(testClass.new Printer(3));

        t1.start();
        t2.start();
        t3.start();
    }

    class Printer implements Runnable {

        private int threadId;

        public Printer(int threadId) {
            super();
            this.threadId = threadId;
        }

        @Override
        public void run() {
            try {
                while (count <= 20) {
                    synchronized (object) {
                        if (threadId != threadIdToRun) {
                            object.wait();
                        } else {
                            System.out.println("Thread " + threadId + " printed " + count);
                            count += 1;

                            if (threadId == 1)
                                threadIdToRun = 2;
                            else if (threadId == 2)
                                threadIdToRun = 3;
                            else if (threadId == 3)
                                threadIdToRun = 1;

                            object.notifyAll();
                        }
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }

        }
    }
}

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About Kartik Chandra Mandal

I am Kartik Chandra Mandal from Bangalore, India. Working as software engineer in Java technology. Have good knowledge of OWASP and CSRF in security for applications and it's implementation in Java technology.

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