package Question10_3;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
public class Question {
public static long numberOfInts = ((long) Integer.MAX_VALUE) + 1;
public static byte[] bitfield = new byte [(int) (numberOfInts / 8)];
public static void findOpenNumber() throws FileNotFoundException {
Scanner in = new Scanner(new FileReader("Chapter 10/Question10_3/input_file_q10_3.txt"));
while (in.hasNextInt()) {
int n = in.nextInt ();
/* Finds the corresponding number in the bitfield by using
* the OR operator to set the nth bit of a byte
* (e.g., 10 would correspond to the 2nd bit of index 2 in
* the byte array). */
bitfield [n / 8] |= 1 << (n % 8);
}
for (int i = 0; i < bitfield.length; i++) {
for (int j = 0; j < 8; j++) {
/* Retrieves the individual bits of each byte. When 0 bit
* is found, finds the corresponding value. */
if ((bitfield[i] & (1 << j)) == 0) {
System.out.println (i * 8 + j);
return;
}
}
}
}
public static void main(String[] args) throws IOException {
findOpenNumber();
}
}