#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <sys/time.h>
#include <sys/resource.h>

#define BILLION 1E9


/* for simplicity the # of procs is defined here,
But a better idea is to read it from the command line */
#define PROCESSES 4
main()
{
int i, pid;

/* Take initial time here */
/* Use clock_gettime(). Do NOT use clock() */

struct timespec requestStart, requestEnd;

clock_gettime(CLOCK_REALTIME, &requestStart);

for(i=0; i<PROCESSES; i++)
    {
    pid = fork();
    if(pid < 0) /* some error occurred – fork failed */
       {
        printf("Error");
        exit(-1);
       }
    if(pid == 0) /* child process code */
        {
        do_work(i, i+1, 20000, PROCESSES);
        exit(0);
        }
    /* do not place any wait() call here */
    }

/* wait for all processes to finish their execution */
for(i=0; i<PROCESSES; i++)
    {
    wait(NULL);
    }

clock_gettime(CLOCK_REALTIME, &requestEnd);

double accum = ( requestEnd.tv_sec - requestStart.tv_sec ) + ( requestEnd.tv_nsec - requestStart.tv_nsec ) / BILLION;
printf( "Time = %lf\n", accum );

/* Take final time here */
/* Use clock_gettime(). Do NOT use clock() */
/* Compute the execution time*/
}


/* this function is executed by each process */
do_work(int nrProc, int inceput, int b, int pas)
{
int i, j, suma_div;


for (i = inceput; i <= b; i += pas) {
		suma_div = 0;
		for (j = 1; j <= i / 2; j++) {
			if (i % j == 0) {
				suma_div += j;
			}
		}
		if (suma_div == i) {
			printf("Proces %d:  %d \n", nrProc, i);
		}
	}

}