练习2014081501

/********************************************************************
@file     Main_practise.cpp
@date     2014-8-15
@author   Tiger
@brief    练习
@details  试编写一个递归函数来确定元素x是否属于数组a[0:n-1]。
********************************************************************/
#include <iostream>

const int SIZE = 5;

bool BinSearch(int arr[], int low, int high, int key);

int main(int argc, const char* argv[])
{
	int arr[SIZE] = {1, 2, 3, 4, 5};
	for (int key=1; key<=6; ++key)
	{
		if (BinSearch(arr, 0, SIZE-1, key))
		{
			std::cout << key << " Find." << std::endl;
		}
		else
		{
			std::cout << key << " Not Find." << std::endl;
		}
	}

	system("pause");
	return 0;
}

bool BinSearch(int arr[], int low, int high, int key)
{
	if (low > high)
	{
		return false;
	}
	else
	{
		int mid = static_cast<unsigned int>(low+high) >> 1;
		if (arr[mid] == key)
		{
			return true;
		}
		else if (arr[mid] > key)
		{
			return BinSearch(arr, low, mid-1, key);
		}
		else
		{
			return BinSearch(arr, mid+1, high, key);
		}
	}
}