title: Why do C++ standards introduce more output methods without input counterparts?
body: <p>C++20 introduces <code>&lt;format&gt;</code>(and sooner C++23 introduces <code>&lt;print&gt;</code>). I like those methods, and I always try to use <code>std::format</code> when it's supported rather than use a series of <code>&lt;&lt;</code>.</p>
  <p>But I notice that this evolution seems to only appear in the output. Why isn't there something like <code>&lt;scan&gt;</code> for input?</p>