title: What is “standard input”?
body: <p>I was tasked with creating a test program in <code>C</code> that reads the contents of the <em>standard input</em> and then prints them.</p>
  
  <p>But I have a little doubt: what is exactly <em>standard input</em>?</p>
  
  <p>Is it what I type in the keyboard? Is it a file I have to read?</p>
  
  <p>Both of them?</p>
  
  <p>And the same goes for <code>standard output</code>: is it the console? a file?</p>