how to sort the list

A) Do you need to write a sorting algorithm to do the sorting on the class member variable?

OR

B) Do you want to know how to sort the class in STL with a class member variable?


For either case, I would recommend writing a functor to help with the comparisons on your class member:

struct CompareYourClassMemberXLess
{
  bool operator()(const YourClass &lhs, const YourClass &rhs)
  {
    // If they reference the same object, return false.
    // This will create a strict weak ordering.
    if (&lhs == &rhs)
      return false;

    return lhs.GetX() < rhs.GetX();
  }
};

// The declaration for the call to "GetX() const" will need to be declared with const.

Create an instance of your functor before you sort:

CompareYourClassMemberXLess CmpXLess;

Now in your sort algorithm, when you want to compare the two values in, you can call the varible CmpXLess like a function to determine where it fits in the search order.

YourClass a;
YourClass b;

CmpXLess(a,b);

for STL use it like this:

std::sort(a.begin(), b.begin(), CompareYourClassMemberXLess());

BTW, feel free to change the obnoxiously long names to something that makes sense in your program. The names will not change the functionality.