/*
 * c++thread1.c++ basic c++ thread
 * $ g++ -Wall -std=c++11 c++thread1.c++ -pthread
 */
#include <iostream>
#include <thread>
using namespace std;
#include <unistd.h>

int fact; 
void factorial(int n){
     fact=1;
     for(int i=1; i<=n; ++i) fact *= i;
     sleep(1);
     cout << "child thread ID: " << this_thread::get_id() << endl;
}

int main(){
    int n;

    cout << "Enter a +ve integer: ";
    cin >> n;
    std::thread t(factorial, n);
    cout << "main thread ID: " << this_thread::get_id() << endl;
    cout << "child thread ID (in parent): " << t.get_id() << endl;
    t.join();
    cout << n << "! = " << fact << endl;

    return 0;
}