poll for properties

[Dimitar Kolev]

Steven Schveighoffer Wrote:

> Please respond to this poll before reading other responses.
> 
> Read the following function:
> 
> void foo(Box b)
> {
>    if(b.xxx)
>      b.fill(5);
>    else
>      b.yyy;
> }
> 
> Assuming you have no idea what type Box is, what of the following options  
> looks most natural for xxx in order to test to see if b has an element in  
> it?
> 
> a) if(b.empty)
> b) if(b.empty())
> c) if(b.clear)
> d) if(b.clear())
> 
> Answer:
> =============
> 

None. I would call it isEmpty or isEmpty().

All of your options are bad names for functions or variables to check the state of an object.

> 
> =============
> 
> What would you guess looks most natural for yyy in order to remove all  
> elements from b?
> 
> a) b.empty;
> b) b.empty();
> c) b.clear;
> d) b.clear();
> 
> Answer:
> =============

All of them as all indicate functions and not states.

> 
> 
> =============
> 
> Which of the following functions looks incorrect?
> 
> void a(Box box)
> {
>     if(box.empty())
>       box.fill(5);
>     else
>       box.clear();
> }
> 
> void b(Box box)
> {
>     if(box.empty)
>       box.fill(5);
>     else
>       box.clear;
> }
> 
> void c(Box box)
> {
>      if(box.clear)
>         box.fill(5);
>      else
>         box.empty;
> }
> 
> void d(Box box)
> {
>      if(box.clear())
>         box.fill(5);
>      else
>         box.empty();
> }
> 
> 
> Answer:
> ==============

I do not find a correct looking one. As I stated you should not make state checking an object with names like that.

> 
> 
> ==============
> 
> You read the documentation for Box, and it looks like this:
> 
> /**
>   * check to see if a box is clear
>   */
>   bool clear();
> 
> /**
>   * empty a box, returning true if the box had contents before emptying
>   */
>   bool empty();

This should return true if it emptied the box not if the box was empty before.

> 
> Now knowing what the actual meaning of clear and empty are, indicate which  
> version(s) of the function in the previous question would surprise you if  
> it compiled.
> 
> Here are the functions again for reference:
> 
> void a(Box box)
> {
>     if(box.empty())
>       box.fill(5);
>     else
>       box.clear();
> }
> 
> void b(Box box)
> {
>     if(box.empty)
>       box.fill(5);
>     else
>       box.clear;
> }
> 
> void c(Box box)
> {
>      if(box.clear)
>         box.fill(5);
>      else
>         box.empty;
> }
> 
> void d(Box box)
> {
>      if(box.clear())
>         box.fill(5);
>      else
>         box.empty();
> }
> 
> Answer:
> ==============

This whole example surprises me.

> 
> 
> ==============
> 
> Do you think the meaning of a symbol with parentheses suggests something  
> different than that same symbol without parentheses for the following  
> symbols:
> 
> a) select
> b) rock
> c) keyboard
> d) elevate
> 
> Answer:
> ==============

a) select - action.
b) rock - could be both but you would know if the application has anything to do with rocks (from the earth)

c) keyboard - I do not think you can say he keyboards. Guess what it should be.

d) elevate - action.

> 
> 
> ==============
> 
> Thank you for taking the poll.  I tried to be as objective as possible, if  
> you don't think I was, please indicate why:

I do not find anything objective here. 

Choosing right names is important and I am sorry but your example does not provide correct naming.

void a(Box box)
{
     if(box.isEmpty())
       box.fill(5);
     else
       box.clear();
}

void b(Box box)
{
     if(box.isEmpty)
       box.fill(5);
     else
       box.clear;
}

I do not find anything wrong with my example. Both cases are perfectly readable and understandable.