What's the difference between terminal & non-terminal symbols in system programming with examples?
A terminal symbol represents a single element of the language, and a non-terminal symbol represents several elements.
terminal and nonterminal symbols are the lexical elements used in specifying the production rules constituting a formal grammar. Terminal symbols are the elementary symbols of the language defined by a formal grammar. Nonterminal symbols (or syntactic variables) are replaced by groups of terminal symbols according to the production rules.
source: http://en.wikipedia.org/wiki/Terminal_and_nonterminal_symbols