Print out bitset quickly in c++

Question

Im writing a program that outputs binary, and I got alot of it I want to output to the terminal, but this takes along time. In other places in my program where I want to quickly output strings I use

_putchar_nolock

and for floating point and decimal numbers I use

printf

Currently my code looks like this for outputting binary numbers

for (size_t i = 0; i < arraysize; i++)
{
    std::cout << (std::bitset<8>(binarynumbers[i]));
}

the output gives a nice 0s and 1s which is what I want, no hex. Issue is when I ran performance benchmarks and testing, I found that std::cout was significantly slower than _putchar_nolock and printf.

Looking online I could not find a way to use printf on a bitset and have it output 0s and 1s. and _putchar_nolock would seem like it would be just as slow having to do all the data conversion.

Does anyone know a fast and efficient way to output a bitset in c++? My program is singlethreaded and simple so I dont have an issue putting unsafe code for performance in there, performance is a big issue in the code right now.

Thanks for any help.

Answer 1

The problem is that cin and cout try to synchronize themselves with the library's stdio buffers. That's why they are generally slow; you can turn this synchronization off and this will make cout generally much faster.

std::ios_base::sync_with_stdio(false);//use this line 

You can also get an std::string from the bitset using the to_string() function. You can then use printf if you want.

Answer 2

I wanted to drop comment don't have enough reps. You can use to_string member of bitset class. This probably should work:

std::cout << std::bitset<8>(binarynumbers[i]).to_string();