title: Compiling and Running a program
body: <p>I am new to computer science and I have doubts :</p>
  <p>Doubt 1:
  If I want the SAME program run 10 times , then would I have to compile the same program 10 times or would I compile the program once and run it 10 times.</p>
  <p>Obviously I would compile the program once and run if it is my first time (to look for errors) , but is it necessary to compile and then run for the next times I would be running the program (assuming I am not making any changes to the program )?</p>
  <p>Doubt2:
  Suppose I have a user input program to find if a number &quot;n&quot; is odd or even .
  The user input is <code>std::cin&gt;&gt;n ;</code>
  My doubt is if the program would compile for every user input (i.e for every change of the variable <code>n</code>)?
  if yes , then it would be a waste of time because the compiler would have to iterate through the entire library and code , but the only change we have done would be changing the value of the variable <code>n</code> .
  (How would I solve the above problem if it had been the case)?</p>