c++：双指针的巧妙应用

问题描述：在一个有序数组中查找两个元素之和为某值，并返回这两个元素，通过定义双指针，不断向前与向后移动来查找，代码较为简单，如下所示：

#include 
using namespace std;
 
bool getTwoSum(int array[], int length,int total, int& leftElem, int& rightElem)
{
	if (nullptr==array||length<=0)
	{
		leftElem = 0;
		rightElem = 0;
		return false;
	}
	int *beginPtr = array;
	int* endPtr = array+length-1;
	while (endPtr>beginPtr)
	{
		int sum = *beginPtr + *endPtr;
		if (sum == total)
		{
			leftElem = *beginPtr;
			rightElem = *endPtr;
			return true;
		}
		else if (sum < total)
		{
			beginPtr++;
		}
		else
			endPtr--;
	}
}
 
int main()
{
	int array[] = { 1,2,4,4,5,6,7,8,9 };
	int leftElem;
	int rightElem;
	if (getTwoSum(array, sizeof(array) / sizeof(array[0]), 11, leftElem, rightElem))
	{
		cout << "can find the two elems: " << leftElem << " " << rightElem << endl;
	}
	else
		cout << "can  not find the two elems" << endl;
	system("pause");
	return 0;
}