baitap1_1.cc

basic about Unix ptheard and pid

#include <sys/types.h>
#include <stdio.h>
#include <unistd.h>
#include <wait.h>
#include <iostream.h>
#include <stdlib.h>

#define MAX_SEQUENCE 10

int main(int argc, char *argv[])
{
	if (argc != 2)
	{
		cout<<"So^' do^i' so^' kho^ng ho*p. le^.\n";
		return 1;
	}
	
	int sequence_size = atoi(argv[1]);
	
	if (sequence_size<0 || sequence_size>MAX_SEQUENCE)
	{
		cout<<"Error\n";
		return 1;
	}

	long fib_sequence[MAX_SEQUENCE];

	fib_sequence[0]=0;
	fib_sequence[1]=1;

        pid_t pid ;
        pid = fork();

        if (pid == 0 )
        {
               for (int i=2;i<sequence_size;i++)
			fib_sequence[i]=fib_sequence[i-1]+fib_sequence[i-2];

		for (int i=0;i<sequence_size;i++)
			cout<<fib_sequence[i]<<endl;
        }
        else if (pid > 0)
        {
              wait(NULL);		         
              _exit(0);
        }

}