“std::endl” vs “\n”

Question

Many C++ books contain example code like this...

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

...so I\'ve always done that too. But

Answer 1

The std::endl manipulator is equivalent to '\n'. But std::endl always flushes the stream.

std::cout << "Test line" << std::endl; // with flush
std::cout << "Test line\n"; // no flush