getbinblocksize(a)

#include <iostream>
using namespace std;
#define B_SHIFT			4	
int getBinBlockSize(int size)
{

	int q = 0;
	for ( q= 0; size>0; size >>= 1)
	{
		q++;
	}

	return 1 << q;
}
static int    getBinBlockSize2(int size)
{
	int    q;

	size = size >> B_SHIFT;
	for (q = 0; size; size >>= 1) {
		q++;
	}
	return (1 << (B_SHIFT + q));
}
int _tmain(int argc, _TCHAR* argv[])
{
	int a;
	cout << "please input a positive integer:";
	cin >> a;
	cout << getBinBlockSize2(a) << endl;
	system("PAUSE");
	return 0;
}