How does “δ:Q×Σ→Q” read in the definition of a DFA (deterministic finite automaton)?

δ is like a mathematical function called the transition function . Something like. z = f(x, y) A function in mathematical defines mapping of elements in one set to another set. In function set of input arguments are called Domain of a function and output is the rage. [ANSWER]    In expression “δ:Q×Σ → Q”, … Read more

Example of Non-Linear, UnAmbiguous and Non-Deterministic CFL?

“IN CONTEXT OF CHOMSHY CLASSIFICATION OF FORMAL LANGUAGE” (1) L3 = {wwR | w ∈ {a, b}* } Language L3 is a Non-Deterministic Context Free Language, its also Unambiguous and Liner language. (2) Lp is language of parenthesis matching. There are two terminal symbols “(” and “)”. Grammar for Lp is: S → SS S … Read more

Need Regular Expression for Finite Automata: Even number of 1s and Even number of 0s

How to write regular expression for a DFA using Arden theorem Lets instead of language symbols 0,1 we take Σ = {a, b} and following is new DFA. Notice start state is Q0 You have not given but In my answer initial state is Q0, Where final state is also Q0. Language accepted by is … Read more

Is there a typical state machine implementation pattern?

I prefer to use a table driven approach for most state machines: typedef enum { STATE_INITIAL, STATE_FOO, STATE_BAR, NUM_STATES } state_t; typedef struct instance_data instance_data_t; typedef state_t state_func_t( instance_data_t *data ); state_t do_state_initial( instance_data_t *data ); state_t do_state_foo( instance_data_t *data ); state_t do_state_bar( instance_data_t *data ); state_func_t* const state_table[ NUM_STATES ] = { do_state_initial, do_state_foo, … Read more

Can regular expressions be used to match nested patterns? [duplicate]

No. It’s that easy. A finite automaton (which is the data structure underlying a regular expression) does not have memory apart from the state it’s in, and if you have arbitrarily deep nesting, you need an arbitrarily large automaton, which collides with the notion of a finite automaton. You can match nested/paired elements up to … Read more