int main()
{
    void *buffer = malloc(40);
    int fd = open("example20.txt", O_RDONLY);
    printf("the value of fd is %d n", fd);


/* read 40 characters from the file */
int bytes_read = read(fd, buffer, 40);

void *new_container = malloc(20);

/* copy from buffer, starting offset at 10 for length of 20 */
memcpy(new_container, &buffer[10], 20);
printf("new_container is %s n", (char *) new_container);

return 0;
}

char *buffer2 = (char *) buffer;
memcpy(new_container, &buffer2[10], 20);

memcpy(new_container, &buffer[10], 20);

memcpy(new_container, (char *)buffer + 10, 20);

&buffer[10]

void *buffer = malloc(40);

unsigned char *buffer = malloc(40);

memcpy(new_container, &buffer[10], 20);

char *buffer = malloc(40);