1

//prime
#include "kernel/types.h"
#include "kernel/stat.h"
#include "user/user.h"

int prime(int fd);

int
main(int argc, char const *argv[])
{
    int pfd[2];
    pipe(pfd);

    int pid;
    pid = fork();
    if(pid==0)
    {
        close(pfd[1]);
        prime(pfd[0]);
        exit(0);
    }
    else
    {
        close(pfd[0]);
        int i;
        for(i=2; i<36; i++)
	{
            write(pfd[1], &i, sizeof(i));
        }
        close(pfd[1]);
	wait(0);
	exit(0);
    }
}

int prime(int fd){
    int base;

    if(read(fd, &base, sizeof(base))==0){
        exit(0);
    }
    printf("prime %d/n", base);

    int p[2];
    pipe(p);
    if(fork()==0){
        close(p[1]);
        prime(p[0]);
    }
    else{
        close(p[0]);
        int n;
        int eof;
        do{
            eof = read(fd, &n, sizeof(int));
            if(n%base!=0){
                write(p[1], &n, sizeof(int));
            }
        }while(eof);
        close(p[1]);
    }
    wait(0);
    exit(0);
}