C++双重指针的区别

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本文链接： https://blog.csdn.net/czp_374/article/details/100527537

#include <iostream>
using namespace std;
struct ListNode
{
	int m_nValue;
	ListNode* m_pNext;
};

void AddToTail(ListNode** pHead, int val)
{
	ListNode* pNew = new ListNode();
	pNew->m_pNext = nullptr;
	pNew->m_nValue = val;

	if (*pHead == nullptr)
	{
		*pHead = pNew;
	}
	else
	{
		ListNode* pNode = *pHead;
		while (pNode->m_pNext != nullptr)
			pNode = pNode->m_pNext;

		pNode->m_pNext = pNew;
	}
}


void AddToTail(ListNode* pHead, int val)
{
	ListNode* pNew = new ListNode();
	pNew->m_pNext = nullptr;
	pNew->m_nValue = val;

	if (pHead == nullptr)
	{
		pHead = pNew;
	}
	else
	{
		ListNode* pNode = pHead;
		while (pNode->m_pNext != nullptr)
			pNode = pNode->m_pNext;

		pNode->m_pNext = pNew;
	}
}

int main()
{
	ListNode* p_nullptr = nullptr;
	ListNode** p_p_nullptr = &p_nullptr;
	AddToTail(p_nullptr, 100);
	
	return 0;
}