Performances of Structs vs Classes

Question

I wonder if there are performance comparisons of classes and C style structs in C++ with g++ -O3 option. Is there any benchmark or comparison about this. I've always thought C++ classes as heavier and possibly slower as well than the structs (compile time isn't very important for me, run time is more crucial). I'm going to implement a B-tree, should I implement it with classes or with structs for the sake of performance.

Answer 1

My honest opinion...don't worry about performance until it actually shows itself to be a problem, then profile your code. Premature optimization is the root of all evil. But, as others have said, there is no difference between a struct and class in C++ at runtime.