Inserts a node into an ascending one-way list

Enter an ascending one-way list and a linked list node to insert the node in ascending order in the unidirectional list.

The case in which the input is a null pointer is treated as an exception, regardless of the value of the node being equal.

The linked list node is defined as follows:

struct ListNode

{

int M_nkey;

listnode* M_pnext;

};

Detailed Description:

Interface description

Prototype:

listnode* insertnodetolist (listnode* plisthead, listnode* pinsertnode);

Input parameters:

listnode* Plisthead unidirectional linked list

listnode* Pinsertnode New Insert Node

Output parameters (the memory area pointed to by the pointer is guaranteed to be valid):

listnode* Plisthead unidirectional linked list

return value:

Normal Insert node returns a chain header pointer, other exception returns a null pointer

#include "OJ.h"
/* Function: Enter an ascending one-way list and a list node to insert this node in ascending order in the unidirectional list. The case in which the
	  input is a null pointer is treated as an exception, regardless of the value of the node being equal.

input: listnode* plisthead  unidirectional linked list
      listnode* pinsertnode new Insert node
      
output: listnode* plisthead  One-way linked list

returns: Normal Insert node returns the link header pointer, other exception returns null pointer
*
/listnode* insertnodetolist (listnode* plisthead, listnode* pinsertnode)
{ /
	* Implement function here */
    
	if (Plisthead = = NULL | | pinsertnode = = NULL)
		return (listnode*) null;
	ListNode *p = Plisthead,*pnext = Plisthead;
	while (pnext!= NULL && Pnext->m_nkey < Pinsertnode->m_nkey)
	{
		p = pnext;
		Pnext = pnext->m_pnext;
	}
	Insert Head pointer position
	if (Pnext = = Plisthead)
	{
		pinsertnode->m_pnext = Plisthead;
		Plisthead = Pinsertnode;
	}
	else
	{
		pinsertnode->m_pnext = Pnext;
		P->m_pnext = Pinsertnode;
	}
	return plisthead;
}