#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>

int main(int argc, char** argv) {

  // file I/O example
  
  // open the file for reading
  int fd = open("a.txt", O_RDONLY);
  if (fd < 0) {
    printf("error opening file\n");
    return -1;
  }

  int nread;
  char buf[1024];  // no string class in C
  while ((nread = read(fd, buf, sizeof(buf))) > 0) {
    // nread is the number of bytes read into buf

    write(1, buf, nread); // write nread bytes from buf to stdout
  }

  // done with the file, close the open file
  close(fd);

  return 0;
}