All 10 I/O Streams questions
More in I/O Streams
What is the difference between std::cout, std::cerr, and std::clog? How do you check for and handle stream errors? How do you read a file with ifstream and write with ofstream? What is the difference between >> and std::getline for input? What is std::stringstream and when is it useful? What are stream manipulators and how are they used? How do you overload operator<< for a custom type? How do you improve iostream performance for large I/O?
Advertisement
Back to results for “I/O Streams”
C++ › I/O Streams

What is the difference between std::endl and '\n'?

Intermediate

Answer

'\n' inserts a newline character. std::endl inserts a newline AND flushes the stream's buffer. Flushing forces output immediately but is comparatively expensive; overusing std::endl in loops hurts performance. Prefer '\n' for normal output and reserve std::endl (or std::flush) for when you truly need an immediate flush.
std::cout << "line\n";     // fast
std::cout << "line" << std::endl; // newline + flush (slower)
Real-world example Replacing std::endl with '\n' in a tight logging loop noticeably speeds up output.

Common follow-ups: What extra work does std::endl do? | When is flushing needed?

I/O Streams I/O Streams I/O Streams
All 10 I/O Streams questions