class Main { public static void main(String[] args) { System.out.println("Hello World!"); int c = 0; do{ System.out.println("["+c+"]: "+calc(c)); }while(c++ <10); } /** * 向上取2的次幂 */ public static int calc(int c){ int n = c - 1; n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16; return n<1 ? 1:n+1; } }