Coming from the HFT side, I find C++ surpasses C in a lot of ways for optimization work. Mainly you can use integer template arguments and generic functions to abstract all the boilerplate in a way that is more safe than C macros.
For a semi-contrived example, instead of writing a do4Things() and do8Things() to unwind some loops, I can write template<int> doThings() where the int argument is the bound on the loop.
And having things like a universal template<typename Whatever> toString() that operates on enum classes is nice.
The downside is that it's horribly easy to invoke allocations and copy constructors by forgetting an ampersand somewhere, and the std library isn't well suited to avoiding that behavior either. You have to be vigilant on your timings and occasionally callgrind the whole thing.
Yeah, the nice thing about C++ is that you can generally hide highly optimized portions of code behind nice templates or class interfaces. And with templates you can write libraries that let a lot of compile time logic happen to inline a bunch of stuff and not have to resort to virtual methods.
But when it comes to using things like custom allocators, etc. it's a nightmare. Or a lot of the compile time "traits".
I have a friend who makes a living writing CUDA kernels as C++ templates. His job will be safe for decades to come because noone will be able to decipher the code. :)
For a semi-contrived example, instead of writing a do4Things() and do8Things() to unwind some loops, I can write template<int> doThings() where the int argument is the bound on the loop.
And having things like a universal template<typename Whatever> toString() that operates on enum classes is nice.
The downside is that it's horribly easy to invoke allocations and copy constructors by forgetting an ampersand somewhere, and the std library isn't well suited to avoiding that behavior either. You have to be vigilant on your timings and occasionally callgrind the whole thing.
The other downside is that your colleagues are more likely to "knit a castle" with ridiculous class hierarchies or over-generalization. ( https://www.infoq.com/presentations/Simple-Made-Easy )