#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>  //errno -l
 
int main(int argc, char *argv[]){
    
    //read 1 byte from "data.txt" and print it out.
    //check that file was opened correctly.

    int fd = open("data.txt",O_RDONLY);
    
    if(fd < 0) {
        //fprintf(stderr, "Could not open file Error code %d\n", errno);
        perror("Could not open file");
        return 1;
    }
     
    unsigned char c; 
    while(read(fd, &c, 1) > 0){
        printf("%c", c);
    }
    
    close(fd);
    return 0;
}