I apologise to all of you for having put the entire code of mine
here, but I am really becoming helpless.
I am trying to write a native palm application in which you have
links similar to the ones used in Web Browser. Clicking on the link (
i.e. an "underlined" text on Palm ) takes you to another form/screen.
I have used a "Queue" class [ please see below ] in which I keep on
adding all the underlined text. This is collected in the form
of "RectangleType" in the "Queue" class.
The "Queue" class has been implemented using Linked List as a Data
Structure. In the implementation of the add() method of this class, I
need to add a new node. While allocating the memory to this node, I
was using "new" keyword. However, it was giving me errors. So I chose
to take the memory dynamically from the "Memory Manager" of the Palm
OS. Even this has not helped. The application compiles smoothly but
at run time when I click on a hyperlink on the Palm screen, the
program crashes and takes me straight to some assembly level
instructions for debugging. The selected function is always add() of
class Queue in this state. I am not at all familiar with assembly
language .
Specifically, what I wanna know is when I create a new object
dynamically, how do I about memory allocation : do I have use "new"
keyword as in a traditional C++ program or do I have to make use of
the methods from Palm OS Memory Manager ?
Please tell me what is going wrong in my code.
Again I apologise for the inconveniency caused to all of you because
of my lack of knowledge.
/*****************************************/
////////// CLASS QUEUE ////////////////
class Queue {
private:
RectangleType rectangle;
int isRed; // color of the underline : red if already visited
else blue
Queue *next; // pointer to the next node
Queue *front, *rear;
// Is thid acceptable ? I am doing like this because I need to
free the memory thru a different function
Queue* temp;
public:
Queue();
void add(RectangleType rect, int color);
RectangleType remove();
int size();
};
Queue::Queue() {
rear = NULL;
front = NULL;
next = NULL;
temp = NULL;
}
void Queue::add(RectangleType rect, int color) {
//Queue *temp; // This is made as a member variable now
//temp = new Queue;
// Here try to the heap from the Memory Manager in lieu of
invoking the new
//unsigned long length = sizeof(rectangle) + sizeof(int);
unsigned long length = sizeof (Queue);
temp = (Queue*)MemHandleLock(MemHandleNew( length ));
if( temp == NULL ) { return ; }
// initialise the data of this node
temp->next = NULL;
temp->rectangle = rect;
temp->isRed = color;
if( front == NULL ) { // null list
front = temp;
}
else {
rear->next = temp;
}
rear = temp;
Err r = MemHandleUnlock ((Queue**)temp) ;
// FrmCustomAlert( AltDebugAlert, " ok ok ok", NULL, NULL );
return ;
}
RectangleType Queue::remove() {
// Queue *temp;
Err error;
RectangleType rect;
temp = front;
rect = temp->rectangle;
if( front == rear ) { // ONE NODE ONLY
front = rear = NULL;
}
else {
front = temp->next;
}
// delete temp;
error = MemHandleFree((void**)temp) ;
return rect;
}
int Queue::size() {
int i = 0;
while( front != NULL ) {
i++;
front = front->next;
}
return i;
}
/************************************************/
--
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