Python Expressive Puzzlers 6: Multicast

底下的Java程式會輸出什麼？

public class Multicast {
  public static void main(String[] args) {
    System.out.println((int) (char) (byte) -1);
}
}

結果不會是 -1。幸運的是有條簡單的規則來說明：「Sign extension is performed if the type of the original value is signed; zero extension if it is a char, regardless of the type to which it is being converted.」也就是 byte -1 === sign extension ==> char 65535 === zero extension ==> int 65535。 而 Python Built-in type 不多，筆者只試了底下兩行：

print(int(str(bytes(-1))))
print(int(chr(bytes(-1))))

輸出結果會是什麼呢？

Originally published at yunlinsong.blogspot.com on August 19, 2018.