#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#define BUFSIZE 256

int main(int argc, char * argv[]){
	int r,x,f,y,n;
	char buf[BUFSIZE];
	if(argc<2){
		fprintf(stdin,"Usage: %s <file>\n",argv[0]);
		exit(1);
	}
	f=open(argv[1],O_WRONLY|O_CREAT|O_TRUNC,0600);
	if(f==-1){
		perror("Opening file failed !");
		exit(2);
	}
	write(1,"Numb --> ",9);
	while((n=read(0,buf,BUFSIZE))!=0){
		r=write(f,buf,n);
		if(r==-1){
			perror("writing failed");
			exit(3);
		}
		write(1,"Numb --> ",9);
	}
	close(f);
	exit(0);
}