ACM Cantoring Along

AC代码：

#include <iostream>
#include <math.h>
using namespace std;

void cantor(int order)
{
    if(order == 0)
        cout << "-";
    if(order == 1)
    {
        cout << "- -";
    }
    if(order >= 2)
    {
        int length = pow(3, order);
        cantor(order - 1);
        for(int i = 0;i<(length / 3);i++)
        {
            cout << " ";
        }
        cantor(order - 1);
    }
}

int main()
{
    int n = 0;
    while(cin >> n)
    {
        cantor(n);
        cout << endl;
    }
    return 0;
}

递归的思路，注意！！void函数的用法。
错误代码：

#include <iostream>
#include <math.h>
using namespace std;

void cantor(int order)
{
    if(order == 0)
        cout << "-";
    if(order == 1)
    {
        cout << "- -";
    }
    if(order >= 2)
    {
        int length = pow(3, order);
        cantor(order - 1);
        for(int i = 0;i<(length / 3);i++)
        {
            cout << " ";
        }
        cout << cantor(order - 1);//错误！！
    }
}

int main()
{
    int n = 0;
    while(cin >> n)
    {
        cout << cantor(n);//错误！！
        cout << endl;
    }
    return 0;
}