A couple of Easy Questions.

[Syre Lancaster]

Hey guys, I've got a couple of questions that are really stumping me on my review and I'm having a hard time finding the answer in my book. Could someone help me out? Here are the first two of the series:
Given the declarations

struct ListNode

{

float volume;

ListNode* next;

};
ListNode* ptr;
what is the data type of the expression ptr->next->next->volume?

a) ListNode*
b) ListNode
c) Float
d) *ListNode
e) none--the expression is invalid





Given the declarations


struct ListNode
{
float volume;
ListNode* next;
};
ListNode* ptr;

which of the following is of type ListNode?

a) ptr
b) *ptr
c) (*ptr).next
d) *((*ptr).next)
e) b and d above


If someone could tell me what the answers are to these I think I can figure the rest out, also a link to some good reference material would not go astray. Thanks!

[Zhuge]

What part of the questions are you having trouble with? Also, it seems you forgot part of the question on the second, as it's asking to select from a list of identifiers presumably but you didn't include that list.

[Syre Lancaster]

There is that better?

[Zhuge]

Yes, now what about my first question?

[Daleth]

In a chain of calls, the overall return type is the same as the last call, so for the first question, you should focus on FOO->volume. Therefore, the final type should be the same as the type of volume.

For the second question, remember that dereferenced pointers return a reference to the type they point to. So in the following:

int a(8);
int* b(&a);
a = *b; //Here *b is of type int 

You can use that knowledge combined with what you know about chains of calls to help you figure the type of each option.



Random Note:
For BAR *FOO, *FOO technically returns BAR&, because you should be able to modify the original object that FOO points to and not a copy.

[Syre Lancaster]

Ahhhhh many thanks. my book was being a bit, "beat-around-the-bush" with the answer. So i take it the first answer would be a float then yes?

[Syre Lancaster]

@Zhuge To answer your question, pretty much all of it. I'm having a hard time wrapping my head around pointers in general, it's like trying to figure out Jewish Dietary restrictions or something.

"You can have X cept when Y happens then you have to do Z unless it's a case of AA"

0.o