CODEWITHSUNDEEP
c++linked-listoperator-overloading
user3265963
user3265963

Reputation: 273

Operator << in a class for queue

I have a small problem with defining my operator:

The code for the operator is:

ostream& operator<< (ostream& outs, const IntQueue& queue)
{
    NodePtr temp = queue.head;
    while(temp->link != NULL)
    {
        outs << temp->data;
        outs << " ";
    }
    outs << endl;
    return outs;
}

I want the operator to display temp->data for all nodes in the queue and also the last node(which points to NULL). I don't know how I can modify the while loop so it also writes out the last item (that points to NULL).

Hope I made myself clear.

Cheers.

Upvotes: 0

Views: 117

Answers (4)

jlouzado
jlouzado

Reputation: 502

A few things to correct :

  • As pointed out in the comments, inside the while loop make sure to advance the pointer with something like

    temp = temp->link;

  • Edit your loop to be a do-while loop. In that way you're sure that it'll print out even the last node.

  • Once you use a do-while loop, you'll need to add an additional NULL check on temp to handle the 'empty' list case.

Finally, as an additional point, you could consider overloading the '<<' operator for the Node object itself. That way your code to print out the entire queue would just be for iterating over the queue as shown below :

ostream& operator<< (ostream& outs, const IntQueue& queue)
{
    Node* temp = queue.head;
    if(NULL != temp) {
        do
        {
            outs << temp;
            temp = temp->link;
        }
        while(temp->link != NULL);
    }
    return outs;
}

Upvotes: 0

Martin J.
Martin J.

Reputation: 5118

Try the following:

ostream& operator<< (ostream& outs, const IntQueue& queue)
{
    NodePtr temp = queue.head;
    while(temp != NULL)
    {
        outs << temp->data;
        outs << " ";
        temp = temp->link;
    }
    outs << endl;
    return outs;
}

Upvotes: 0

Vlad from Moscow
Vlad from Moscow

Reputation: 310990

ostream& operator <<( ostream& outs, const IntQueue& queue )
{
    for ( NodePtr temp = queue.head; temp; temp = temp->link )
    {
        outs << temp->data;
        outs << " ";
    }

    outs << endl;

    return outs;
}

Upvotes: 3

Alex Johnson
Alex Johnson

Reputation: 534

You could try to use a do-while loop so that it wouldn't check for the NULL until after it had done the operation the last time.

I would imagine this would allow you to print out NULL as the final value.

Upvotes: 0

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