Explain the usage of ctags.

• It is a programming tool that generates index file of names found is source and header file. 
• It is used in many programming languages.
• Functions, variables, class names, structures, macros are indexed, but what all names can be indexed depends on the programming language.
• Most commonly used ctags with vim editor is Exuberant Ctags.

Useful Commands

• To enable ctags in a source file give the command ctags -R *
• It parses all the names and creates a stack for each name.
• To view the definition of a function or a structure we need to take our cursor over it and enter ctrl+] command.
• To come back to fucntion call from definition we use ctrl+t.
• Following vim commands can be used to navigate through relevant functions
  
• :ts or :tselect shows the list
• :tn or :tnext goes to the next tag in that list
• :tp or :tprev goes to the previous tag in that list
• :tf or :tfirst goes to the first tag of the list
• :tl or :tlast goes to the last tag of the list