CS210 Lab: Queue Prelab Answers

Prelab Answers:

1. Give the values of the following expressions

a.  ptr1->data	22
b.  ptr2->next->data	75
c.  head->next->next->data	34

2. Are the following expressions true or false

a.  head->next == ptr1	TRUE
b.  ptr1->next->data== 46	FALSE
c.  ptr2->next == NULL	FALSE
d.  head->data == 12	TRUE

3. Decide whether the syntax of each of the following statements is valid or invalid. If it is valid, mark it as such; if it is invalid, explain what is wrong.

   a.  head->next = ptr1->next;	VALID
   b.  head->next = *(ptr2->next);	INVALID--cannot assign a "LinkNode" to a "NodePointer". The following is correct: head->next = ptr2->next;
   c.  *head = ptr2;	INVALID--cannot assign a "NodePointer" to a "LinkNode". The following is correct: head = ptr2;
   d.  ptr2 = ptr1->next->data;	INVALID--cannot asssign an "integer" to a "NodePointer". The following is correct: ptr2->data = ptr1->next->data;
   e.  ptr1->data = ptr2->data;	VALID
   f.  ptr2 = ptr2->next->next;	VALID

4. Write one statement to do each of the following:

   a.  Make head point to the node containing 34.	head = ptr1->next;
   b.  Make ptr2 point to the last node in the list.	ptr2 = ptr2->next;
   c.  Make head point to an empty list.	head = NULL;
   d.  Set the data member of the node containing 34 to 45.	ptr1->next->data = 45;