Tolong jelaskan mengenai complex *p = NULL; dari Basa program dalam bahasa sunda

complex abs_p = sqrt (p->réal * p->réal + p->im * p->im);

The grammar needed to specify a programming language can be classified by its position in the Chomsky hierarchy.  The syntax of most programming languages can be specified using a Type-2 grammar, i.e., they are context-free grammars.