title: Analyzing a string for file name format
body: <p>A file name is being passed down into a function. The string needs to be checked to make sure it ends with ".bmp" </p>
  
  <p>How do i check for that to later open the file?</p>
  
  <p><strong>For example</strong>: if a string contains "<em>picture.txt</em>" it will tell the user the string is not in the correct format. If a string contain "<em>picture.bmp</em>" it should accept it for later use of opening the file. </p>
  
  <p>Thanks in advance!</p>