C++ :: Randomizing Order Of If-else Statements

The purpose of doing this is so that the top of the if statements is not preferred over the bottom. I tried assigning enum values to each case. Then choose a random integer r from 0 to the size of the std::list myList containing those enum elements. The enum value is found using it = std::next (myList, r). Then if the if statement corresponding to that enum value is false, then myList.erase (it), and repeat the process with the newly reduce myList. It works, and everything seems nicely randomized. But it is disappointing much slower than when I used the original if-else statements (it is being applied hundreds of times).

Here is a snippet of my code (I decided not to use switch statements because it looked too clumsy):

std::list<FacingDirection> guyFacingDirections = {Positive_x, Negative_x, Positive_y, Negative_y, Positive_xPositive_y, Positive_xNegative_y, Negative_xPositive_y, Negative_xNegative_y};
while (true) {
const int r = rand() % guyFacingDirections.size();

[Code] .....

There is a crowd of girls. Each guy will choose a girl, and then choose a facing direction to dance with his chosen girl. But not all facing directions are possible if someone is standing at the spot he wants to stand at to get his desired facing direction. Without randomizing the if-else statements, most of the guys will end up facing the same direction, which I don't like.