Why do several of the standard operators not have standard functors?

Question

We have:

• std::plus (+)
• std::minus (-)
• std::multiplies (*)

Answer 1

All of the ones listed are two-argument functors. Not all of the ones below are. In fact, only >>, <<, &, |, and != fulfill that criterion, and are just a little less useful in terms of functors. The casts especially are templates, which makes them a little less useful.