How to implement case insensitive fncs?

[tienweiwei]

Implement AccessIgnoreCase() to count the number of stations from the head to a destination using linked list.
for e.g.
PoLam->HangHau->TseungKwanO->TiuKengLeng->YauTong->QuarryBay->NorthPoint->NIL

Implement Access() which is case sensitive. However, it crashes when input does not match the string. How can I resolve this and how can I write a AccessIgnoreCase() which is case insensitive?


int List::Access(string str)
{
if (m_Head == NULL)
return -1;
else
{
if (m_Head->str == str)
return 0;
else
{
int counter = 0;
Node* current;
current = m_Head;

while (current!= NULL)
{
counter++;

if (current->ptrNext->str == str)
return counter;
else
current = current->ptrNext;
}
if (current == NULL)
return counter;
}
return -1;
}
}

[jkmyoung]

Here's your problem:
if (current->ptrNext->str == str)
All you know is current != null.
You don't know if current->ptrNext ?= null, which it does when the program crashes.
Change it to
if (current->str == str)
and adjust your counter accordingly, eg maybe put the increment at the end of the loop.

Use a string function to convert both strings to lower case. eg:
http://www.dreamincode.net/code/snippet39.htm