打印n位数的最大值

public static void main(String[] args) {
        char[] number =new char[3];
        generateNum(number, 0);
    }
    public static void printNum(char[] number){
        int i=0;
        while(i<number.length && number[i] == '0')
            i++;        
        for(;i<number.length;i++){
            System.out.print(number[i]);
        }
        System.out.println();
    }
    
    public static void generateNum(char[] number,int index){
        if(index == number.length){
            printNum(number);
            return;
        }
        
        for(int i= 0;i<10;i++){
            number[index] = (char)('0'+i);
            generateNum(number, index+1);
        }
    }