为什么Java中的System.out.println（-1 << 32）= - 1？

Question

Why does System.out.println(-1<<32) display -1 in Java? Is there any root cause? I hope somebody can explain!

Answer 1

In Java (and JavaScript), a << b automatically wraps b modulo the bit length of the numeric type. You're doing it with an int , which is 32 bits, and 32 % 32 = 0, therefore, no change. You can always just check for a b of more than (bit length - 1) and automatically set to zero instead of shifting.