CODEWITHSUNDEEP
c++
Hasan Sammour
Hasan Sammour

Reputation: 27

Finding negative values in SLL

I'm required to traverse through a singly linked list and find the negative nodes, delete them and return the number of delete nodes.

This is the code i have so far, but I always get counter=1 returned from the function

Is there anything wrong in the for loops and if statements, or is it something else 

bool IntSLList::DeleteNegativeNodes()
{
int counter=0;
if(IsEmpty() == true)
    counter++;

if(head->val<0)
{
    DeleteFromHead();
    counter++;
}

if(tail->val<0)
{
    DeleteFromTail();
    counter++;
}


IntSLLNode *node, *pred, *tmp;
node = pred = NULL;


for(pred = head, node = head->next; 
    node != NULL; 
    node = node->next, pred = pred->next)
{
    if(node->val<0)
    {
        node->flag = 1;

    }
}
for(tmp = head; tmp != NULL; tmp = tmp->next)
{
    if(tmp->flag==1)
    counter++;
    delete tmp;


}
return counter;
}

int main()
{
int n,x,z;
IntSLList list1;


cout <<"Insert number of nodes u'd like inserted in list" << endl;
cin >> n;

for(int i=0;i<n;i++)
{
    cin >> x;
    list1.AddToTail(x);
}
z=list1.DeleteNegativeNodes();

cout << "Number of negative deletes nodes is : " << z << endl;

 }

Upvotes: 0

Views: 368

Answers (2)

Nikita
Nikita

Reputation: 6427

The problem is in the type of the return value. Check the signature of the method:

bool IntSLList::DeleteNegativeNodes()

Return type is bool there. When you return counter of type int from your method it's implicitly converted to bool. Zero value becomes false. All other values become true.

On the caller side:

z=list1.DeleteNegativeNodes();

bool value is implicitly converted to int. Because of it you get 1.

Change the return type of DeleteNegativeNodes to int to fix the problem.

Upvotes: 1

Alex P
Alex P

Reputation: 48

In the second for you have

if(tmp->flag==1)

And I think you have to use 

if(node->flag==1)

Upvotes: 0

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