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)?

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.