C/C++ Functions - How are prototypes allowed? : <p>Title.</p>

<p>Assuming(<em>because, as a beginner, I'm not sure</em>) a source code is read from top to bottom by the compiler. How does the compiler understand what actions are supposed to be performed when a function is called in the main function, if the said called function is not yet defined?</p>

<p>Thanks.</p>
