数据结构练习（28）输出1到最大的N位数

#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;
}