二分搜索的遞歸與非遞歸實現

1.遞歸方式對有序表進行折半查找

template<class E, class K>                           // SortedList模板類，E元素類型，K關鍵碼類型
int SortedList<E, K>::BinarySearch(const K x, int low, int high)
{
	int mid = 0;
	if(low <= high)
	{
		mid = (low + high)/2;
		if(x > Element[mid].key)
			mid = BinarySearch(x, mid+1, high);
		else if(x < Element[mid].key)
			mid = BinarySearch(x, low, mid-1);
	}
	return mid; 
}

2.非遞歸方式對有序表進行折半查找

template<class E, class K>
int SortedList<E, K>::BinarySearch(const K x)const
{
	int high = m_iCurrentSize - 1;
	int low  = 0;
	int mid  = 0;
	while(low <= high){
		mid = (low + high)/2;
		if(x > Element[mid].key)
			low = mid + 1;
		else if(x < Element[mid].key)
			high = mid - 1;
		else return mid;
	}
	return 0;
}