#include <iostream>
#include <unistd.h>
#include <vector>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>

using namespace std;

const int NAP_TIME = 5;

int myid;
bool loop = true;

void sigHandler(int sig) {
   loop =  false;
   cout << "CHILD: " << myid << " or " << getpid() 
        << " got hit with a " << sig 
        << " and is now exiting " << endl;

   return;
}

int main() {

    vector<pid_t> children;

    int nprocs = 5;
    int i;
    pid_t child;
    int wstatus;
    int coin;

    if (signal(SIGHUP, sigHandler)== SIG_ERR) {
       perror("signal");
    }


    srand(time(NULL));
    coin = rand()%nprocs + 1;
    cout << "PARENT: Child with id " << coin << " will exit " << endl;

    myid = 0;
    for(i = 1; i <= nprocs and myid == 0; i++) {
        child = fork();
	if (child == 0) {
	    myid = i;
	} else {
	    children.push_back(child);
	}
    }

    cout << getpid() << " is process number " << myid << endl;
   
    if (myid > 0) {
       if (coin == myid) {
          // randomly selected child to exit after a while
          sleep(NAP_TIME);
          cout << endl;
	  cout << "CHILD: id " << myid 
	       << " won the coin toss and will now exit " << endl;
	  return 0;
       } else {
          // other childern
          while (loop) ;
	  cout << "Exit by id " << myid << endl;
       }

    } else {
       // parent

       child = wait(&wstatus);

       cout << endl;
       cout << "PARENT: Child with pid " << child << " exited " << endl;
       cout << "PARENT: Forcing an exit on all other children " << endl;

       for(i=0;i<children.size();i++) {
          if (children[i] != child) {
	     cout << "PARENT: Hitting " << children[i] << " with a hup " 
	          << endl;
	      kill(children[i], SIGHUP);
	  }
       }
        
    }
    return 0;
}