void pc(int m,int n,int &position,int (&a)[100])
{
	//如果运算得到那个数
	if (position == m )
	{
		for (int i = 0; i < m; i++)
		{
			cout << a[i]<<' ';
		}
		cout << endl;
		position--;
	}
	else//如果家没有到我们要找的m就继续寻找
	{
		for (int i = 0; i < n; i++)
		{
			if (position == 0)
			{
				a[position] = i + 1;
				position++;
				pc(m, n, position,a);
			}
			else
			{
				if (i > (a[position - 1] - 1))
				{
					a[position] = i + 1;
					position++;
					pc(m, n, position,a);
				}
			}
		}
		position--;
	}
}

	int n;//n是要排列的个数
	int all = 1 << n;
	for (int i = 0; i < all; i++)
	{
		//其实二进制的一步一步的进位就是对n个数的全遍历
	}