CODEWITHSUNDEEP
c++printfcoutio-redirection
user3081810
user3081810

Reputation: 9

Is using Redirection to print to file in C++ faster than using the convectional cout?

I'm working on a code that performs the Josephus's permutation. I noticed that when I use redirection, its faster than when I use cout or printf. Please I would like to know from anyone having experience, which one is usually faster as i am mostly concerned with code performance and timing.

Thanks.

Upvotes: 1

Views: 329

Answers (1)

manlio
manlio

Reputation: 18902

It depends on your OS an your platform's implementation of the C and C++ I/O libraries (... and cpu load, services, processes, RAM...).

On Windows, writing to the console is a huge bottleneck. Usually it's faster on Linux / MacOS (e.g. Performance difference of iostream console output between Windows and OSX?).

Writing to an ofstream directly could increase performance if it uses a different buffering scheme compared to cout (and this is often the case).

Anyway with streams you can speed up the printing significantly using '\n' instead of std::endl:

  std::cout << "Test line\n";

is faster than:

std::cout << "Test line" << std::endl;

since the latter is equivalent to:

std::cout << "Test line\n" << std::flush;

(see C++: "std::endl" vs "\n" for further details).

Some references:

Upvotes: 1

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