English: Scanner (a.k.a. lexer) and parser example for C. Starting from the sequence of characters "if(net>0.0)total+=net*(1.0+tax/100.0);", the scanner composes a sequence of tokens, and categorizes each of them, e.g. as identifier, reserved word, number literal, or operator. The latter sequence is transformed by the parser into a syntax tree, which is then treated by the remaining compiler phases. The scanner and parser handles the regular and properly context-free parts of the grammar for C, respectively.