java 进制转化

    public static void toBinary(int num){
        trans(num,1,1);
    }
    public static void toHex(int num){
        trans(num,15,4);
    }
    public static void toOctal(int num){
        trans(num,7,3);
    }
    public static void trans(int num,int base,int offset){
        if(num==0){
            System.out.println('0');
            return;
        }
        char[] chs={'0','1','2','3',
                    '4','5','6','7',
                    '8','9','A','B',
                    'C','D','E','F'};
        char[] ch = new char[32];
        int pos=ch.length;
        while(num!=0){
            
            int temp = num & base;
            ch[--pos] = chs[temp];
            num = num >>> offset;
        }
        //System.out.println("pos="+pos);
        for(int x=pos;x<ch.length;x++){
            System.out.print(ch[x]);
        }
        System.out.println();
    }