数据结构练习（28）输出1到最大的N位数

http://zhedahht.blog.163.com/blog/static/2541117420094279426862/

思路：

简单的题目就要尽量要用简洁的代码来搞定，此时要求体现的是程序的逻辑性，切记。

#include <cstdio>
#include <cstring>
#include <cstdlib>

void PrintNumber(char* s, int len)
{
    bool flag = true;

    for (int i = 0; i < len; ++i)
    {
        if (flag && s[i] != '0')
            flag = false;

        if (!flag)
        {
            printf("%s\n", &s[i]); break;
        }
    }
}

void PrintNumberRecursively(char* s, int len, int index)
{
    if (index == len - 1)
        PrintNumber(s, len);
    else
    {
        for (int i = 0; i <= 9; ++i)
        {
            s[index+1] = i + '0';
            PrintNumberRecursively(s, len, index + 1);
        }
    }
}

void solve(int n)
{
    if (n <= 0)
        return;

    char b[100];
    memset(b, '\0', sizeof(b));

    for (int i = 0; i <= 9; ++i)
    {
        b[0] = i + '0';
        PrintNumberRecursively(b, n, 0);
    }
}

int main()
{   
    solve(2);
    return 0;
}