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Comment by khitchdee | Hacker News Reader

C++ is slow and bloated but people just hide that under the rug.

C++ is a language, while iostream is one of the many C++ tools available to write to the standard output. It’s available by default, it’s part of the standard library, but you don’t have to use it. printf is also available, and will be as fast as using it from C.

Note that in most cases, the speed of writing to standard output is irrelevant unless you are implementing cat or some command line text processing tool.

I find iostream very convenient and type safety is a big plus compared to printf. It’s also very easy to implement your own handlers for your own types.

C++ adds a layer of functional indirection above the level of the C structure. This is what causes the bloat. The implementation of the C++ object vs. the C struct. Iostream is implemented as an object. C++ is definitely more convenient and that was the intent of its creators. It does not replace C but provides a more convenient alternative to using C structs and fn pointers at the cost of a small performance penalty (maybe slow and bloated is over-expressing the penalty).

This "bloat" of C objects you mention is only there if you use virtual functions. Same as using function pointers in a C struct. But in some cases C++ can avoid the dynamic indirection thanks to templates like in std::sort while C's qsort gets passed a function pointer, called for each comparison.

Iostream do use virtual functions but it’s not the reason of its suboptimal performance. The main reason is that some strings will be copied, allocated and freed during the construction of the whole expression while printf can do its processing with minimal dynamic allocations.

No virtual fns means no inheritance. Also, you can blame the implementation and not the language. But real-world it is slower. Can't say by how much. Why bother?

I don't believe anyone tries to hide it. Except a couple of well-known cases, C++ is (relatively slightly) slower than C, but it's far more powerful. You can argue about compile times - yes, there is a huge difference here; also some specific features like virtual methods are slow - but overall, C++ is one of the fastest languages available.

C++ includes plenty of tools, including a C11 subset, so if it happens to be slower than a bare bones C compiler, the author doesn't know its craft.

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