what to return ?

[andrix]

hi
i have a general question about a function that i'm using in a binary tree.

the function has to return the value of the father of the node containing the value n;
but if n is the value in the root, what should i return?
this function should return an int

thanks

[Cubbi]

If the values in the nodes are restricted to some subset of ints (e.g. INT_MIN is never stored on the tree), then you can return one of the forbidden values to indicate this condition (similar to how many functions of std::string return the special value std::string::npos)
Otherwise, you'd have to throw an exception, or, better, redesign.

[andrix]

ok thanks
same for example in this case right?

for example searching the max value in a tree

int max(node *ptr)
{
if(ptr!=NULL){

//search for the max

}
else return INT_MIN
}

is it correct?

[Cubbi]

For max search, yes, you could return INT_MIN as the special value.. or you could redesign to avoid getting called on null pointers in the first place.

[JLBorges]

Return std::optional<int> (C++14) or boost::optional<int>?

http://www.boost.org/doc/libs/1_54_0/libs/optional/doc/html/index.html
http://en.cppreference.com/w/cpp/utility/optional

[andrix]

returning INT_MIN actually causes an error, the compiler doesn't know INT_MIN.
is it contained in any special library?

[JLBorges]

INT_MIN requires #include <climits>

std::numeric_limits<int>::min() requires #include <limits>