title: how to make the user have the correct input type in c
body: <p>I just started learning c programming, my question might be so silly.</p>
  <p>I try to create a function to grab user input using scanf(). before that, I will have the menu displayed, and the user should only enter a number. so there is my question, how can I check whether the user enters an integer or character string or any other symbol. and send an error message if they do so?</p>