static void Main(string[] args)
{
var stackElementO = "<0>";
var alphabet = new string[] { "(", ")" };
//Stack alphabet consists of all non-terminals + the initial stack symbol
var stackAlphabet = new string[] { stackElementO, PDA.initialStackSymbol };
//Transition from state 0 to state 1 (first and second parameters)
//We read ( from input (third parameter)
//We pop Z0 (the initial stack symbol) from stack (fourth parameter)
//We push <0> and Z0 to stack (last parameters, we can have more than one at a time)
var transitionStart = new PDATransition(0, 1, "(", PDA.initialStackSymbol, stackElementO, PDA.initialStackSymbol);
//Transition from state 1 to state 1
//We read ( from input
//We pop <0> from stack
//We push <0><0> to stack
var transitionOpen = new PDATransition(1, 1, "(", stackElementO, stackElementO, stackElementO);
//Transition from state 1 to state 1
//We read ) from input
//We pop <0> from stack
//We push nothing (empty string) to stack
var transitionClose = new PDATransition(1, 1, ")", stackElementO, "");
//Transition from state 1 to state 2 (final)
//We read nothing (empty string) from input
//We pop Z0 from stack
//We push nothing (empty string) to stack
//As a result both input and stack are now empty
//We will successfully finish our recognition process
var transitionFinal = new PDATransition(1, 2, "", PDA.initialStackSymbol, "");
var transitions = new PDATransition[] { transitionStart, transitionOpen, transitionClose, transitionFinal };
var states = new HashSet <int> {
0, 1, 2
};
var pda = new PDA(alphabet, stackAlphabet, states, 0, transitions);
//Recognizing valid string, expecting successfull result
Show(pda.Recognize(pda.Split("(()())")));
//Recognizing invalid string, expecting NotRecognized result
Show(pda.Recognize(pda.Split("(()")));
//Generating string using our pushdown automaton
var generatedString = pda.Generate();
Console.WriteLine(String.Join("", generatedString));
//Recognizing generated string, obviously expecting successfull result
Show(pda.Recognize(generatedString));
}
