title: Why does this online compiler allow me to compile the code even if the functions are not declared before the main?
body: <p>online compiler: <a href="https://www.onlinegdb.com/online_c_compiler#" rel="nofollow noreferrer">https://www.onlinegdb.com/online_c_compiler#</a></p>
  
  <p>Why does this compiler let me compile a code without the functions before the main function? Shouldn't it be an error?</p>