delete prev elem if..

Hello I have home work in c++: write function whose delete those elements who next element is even.

For example i have this list: 4 2 2, the result of this function mus be: 2. other example: 4 1 2 2, result: 4 2.

I write such function, but with this examples my function make errorin other way my function works correctly. Where can be error in this function?:

structure:

Code:

---

struct elem
{
        int n;
        elem *next;
};

---

function:

Code:

---


void remake(elem *&first)
{
    elem *curr=first;
    elem *prev=NULL;
    elem *pprev=NULL;
     
  while(curr!=NULL)
  {
          pprev=prev;
      prev=curr;
      curr=curr->next;
               
      if(curr!=NULL)
          {
                  if(curr->n%2==0)
                  {
                          if(pprev==NULL)
                          {
                                  delete prev;
                                  first=curr;
                                  prev=curr;
                          }
                          else
                          {
                                  pprev->next=curr;
                                  delete prev;
                                  prev=pprev;
                          }
                  }
          }
  }
};

---

Can you describe what type of error you are getting? A segmentation fault or something?

Also, remake() is a bad name for a function. Be imaginative. :)

Why remake() is bad, i like it. Transform will be better? :)

Not exactly error I get, but wrong result:
for input data 4 2 2 I get output result -572662307.

I think there is some problems with NULL's somewhere. But I dont know where..

In your case where you're deleting the head of the list, should prev not get reset to NULL (rather than curr)?

Quote:

---

Originally Posted by xeniox

Why remake() is bad, i like it. Transform will be better? :)

---

Well, it doesn't tell you anything about what the function does. remove_before_even() would be a better name, for example.