C++ Linked List Search Error: STATUS_ACCESS_VIOLATION - c++

Question

I am writing a program that adds, deletes, and displays nodes (that are doubly linked) and their components, but whenever I try to retrieve a node and display it's components I get this error:
2 [main] a 4640 exception::handle: Exception: STATUS_ACCESS_VIOLATION
2875 [main] a 4640 open_stackdumpfile: Dumping stack trace to a.exe.stackdump
I have narrowed it down to the search function within my .h file that is supposed to search to see if there is a node within the linked list that account number being searched. The function returns the node that comes before it, or the "previous" node.
Here is my search function:
bool searchListByAcctNum (int searchKey, nodePtr *prevOut)
{
bool found = false;
nodePtr p = headNum;
nodePtr prev = NULL;
while (p != NULL)
{
if (p->acctNum < searchKey)
{
prev = p;
p = p->nextNum;
}
else
{
if (p->acctNum == searchKey)
found = true;
p = NULL;
}
}
*prevOut = prev;
return found;
If anyone could help me at all, I'd appreciate it!

Answer 1

It looks like your list may be corrupted, or the pointer you're passing to receive the previous node is invalid, since that code looks okay. However, it seems to me that it could be written in a much simpler manner:
bool searchListByAcctNum (int searchKey, nodePtr *prevOut) {
/// Start at beginning of list, use pointer variable to hold previous.
nodePtr p = headNum;
*prevOut = = NULL;
// Process entire list, will exit early if need be.
while (p != NULL) {
// If past it, just return false, caller should ignore prevOut.
if (p->acctNum > searchKey)
return false;
// If equal, return true, prevOut holds previous or NULL if found at start.
if (p->acctNum == searchKey) {
return true;
// Save previous and advance to next.
*prevOut = p;
p = p->next;
}
// Reached end of list without finding, caller should ignore prevOut.
return false;
}