10.10

/*
 * 10.10.c
 */
#include <stdio.h>
#include "csapp.h"

int main(int argc, char* argv[]) {
  int n;
  rio_t rio;
  char buf[MAXLINE];

  if (argc == 2) {
    int fd = Open(argv[1], O_RDONLY, 0);
    while ((n = Rio_readn(fd, buf, MAXBUF)) != 0)
      Rio_writen(STDOUT_FILENO, buf, n);
    exit(0);
  }

  Rio_readinitb(&rio, STDIN_FILENO);
  while ((n = Rio_readlineb(&rio, buf, MAXLINE)) != 0)
    Rio_writen(STDOUT_FILENO, buf, n);

  return 0;
}