开个麻将馆需要办什么证呢

public class Change { public static void main(String[] args) { System.out.println(binary(100)); System.out.println(octonary(100)); System.out.println(hexadecimal(1000)); } public static String binary(int a){ byte[] b = new byte[1024]; String s=""; int i=0; while(a>0){ int temp = a%2; b[i] = (byte)temp; i++; a = a/2; } while(--i>=0){ s+=b[i]; } return s; } public static String octonary(int a){ String s = ""; byte [] b = new byte[1024]; int i =0; while(a>0){ int temp = a%8; b[i] =(byte)temp; i++; a /=8; } while(--i>=0){ s += b[i]; } return s; } public static String hexadecimal(int a){ String s =""; byte [] b = new byte[1024]; int i=0; while(a>0){ int temp = a; b[i] = (byte)temp; i++; a /= 16; } String [] str = {"A