sorting

[bhatiaharsh]

Hi,

I know one working solution of my sorting problem, but I am curious if there is a better way to handle this. Please share your opinion.


I have a class A, for which I am defining the operator <. However, this comparison function needs access of an object of other class B. I dont wish to store the object of (or even pointer of) B in the objects of class A. Instead, I am defining a global pointer to the object of B, which is assumed not null in the comparison.

B* objB = NULL;

bool A::operator< (const A &fv) const{

    if(objB == NULL)
        throw std::invalid_argument("A::operator<  -- Cant compare since objB is NULL!");

    /* ----
       comparison logic 
    */
}

However, what this means is that when creating a set of objects of A, I need to set the pointer objB.

objB = some value

set<A> setA;
/* ----
 start inserting values
*/

This gets messy, especially if the code spans multiple files, and i need to use

extern B* objB

What would be a more elegant way to handle such a case ?

[ne555]

Don't use the operator< but a comparison class.
http://cplusplus.com/reference/set/set/set/
set<A, compare> setA( compare(objB) );

Every set has its own compare object.
According to your needs, the objB can be shared.

[bhatiaharsh]

Great. Thanks.