面试题12：打印1-3位的数字

package _12_printOneToN;
/**
 * 打印1-3位的数字,使用类似全排列方法
 * 每次递归都循环取0-9，输出时移除首位0
 * @author yanjie
 *
 */
public class PrintOneToN {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		char[] data={'0','1','2','3','4','5','6','7','8','9'};
		int n = 2;
		fun(data, "", 1, n);
	}
	/**
	 * 
	 * @param data 数组
	 * @param s 临时字符串，s=s+data[n],结束条件n>k
	 * @param k 递归多少次，从1开始
	 * @param n 递归深度,表示位数
	 */
	public static void fun(char[] data,String s, int k, int n){
		if(k>n){
			System.out.print(rmZero(s)+" ");
			return;
		}
		for(int i=0; i

package _12_printOneToN;
/**
 * 打印1-3位的数字,模拟字符串加法
 * @author yanjie
 *
 */
public class PrintOneToN1 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int n = 3;
		printOneToN(n);
	}
	
	public static void printOneToN(int n){
		String num = "1";
		while(num.length() lenB ? lenA : lenB;  
        int[] result = new int[len + 1];  
        for (int i = 0; i = 10) {  
                result[i + 1] += result[i] / 10;  
                result[i] %= 10;  
            }  
        }  
        StringBuffer sb = new StringBuffer();  
        //该字段用于标识是否有前置0，如果有就不要存储  
        boolean flag = true;  
        for (int i = len; i >= 0; i--) {  
            if (result[i] == 0 && flag) {  
                continue;  
            } else {  
                flag = false;  
            }  
            sb.append(result[i]);  
        }  
        return sb.toString();  
    }
}