Implement the Queue ADT, using a list   such that the rear of the queue is at the end of the list.
 
      Another example of the parentheses matching problem comes       from hypertext markup language (HTML). In HTML, tags exist in       both opening and closing forms and must be balanced to       properly describe a web document. This very simple HTML       document:     
                            

Hello, world

is intended only to show the matching and nesting structure for tags in the language. Write a program that can check an HTML document for proper opening and closing tags.