title: What does 'note: expanded from macro 'bool' #define bool _Bool' mean?
body: <p>I have looked and looked and I don't know what this error means. I am trying to write a C program that determines whether a triangle is valid, but when I make it in the command line it seems to tell me something is wrong with bool. I have really spent some time on this and I am just not sure how to get this to run. </p>
  
  <p><a href="https://i.stack.imgur.com/9IhXh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9IhXh.png" alt="Here is my code"></a></p>