title: Visual Studio can't debug, can only attach
body: <p>I cannot press <kbd>F5</kbd> to debug my program, because there is only an <kbd>Attach...</kbd> button instead of a <kbd>Debug</kbd> button.</p>
  
  <p>I am using a .c source file, and I was able to debug my sources until I changed a .cpp to a .c and now every source file I open, it says "Attach...". What do I do?</p>