L(PDA) = {anbn | n>0}
class Stack:
def __init__(self):
self.stackliste = []
self.stacklistenlaenge = 0
def pop(self):
if self.istLeer() == False:
self.stacklistenlaenge = self.stacklistenlaenge - 1
return self.stackliste.pop()
def peek(self):
if self.istLeer() == False:
return self.stackliste[self.stacklistenlaenge - 1]
def push(self, inhalt):
self.stackliste.append(inhalt)
self.stacklistenlaenge = self.stacklistenlaenge + 1
def getStacklistenlaenge(self):
return self.stacklistenlaenge
def istLeer(self):
if self.stacklistenlaenge <= 0:
return True
else:
return False
#---------------------------------------------------
def Zustandsuebergangsfunktion(symbol):
global state
if state == "q0":
if symbol == "a":
state = "q1"
pdaStack.pop()
pdaStack.push("Z")
pdaStack.push("P")
return True
else:
return False
if state == "q1":
if symbol == "a":
pdaStack.pop()
pdaStack.push("P")
pdaStack.push("P")
state = "q1"
return True
elif symbol == "b":
pdaStack.pop()
state = "q2"
return True
else:
return False
if state == "q2":
if symbol == "b":
if pdaStack.peek() == "P":
state = "q2"
pdaStack.pop()
if pdaStack.peek() == "Z":
state = "q3"
return True
else:
return False
if state == "q3":
if pdaStack.peek() == "Z":
pdaStack.pop()
return True
else:
return False
#---------------------------------------------------
def Akzeptor(wort):
global state
for i in range(len(wort)):
testsymbol = wort[i]
aktzustand = Zustandsuebergangsfunktion(testsymbol)
print("Zustand: ", state, "\tAktueller Stack: ", pdaStack.stackliste)
if aktzustand == False:
return False
if pdaStack.peek() == "Z" and state == "q3":
return True
else:
return False
#---------------------------------------------------
pdaStack = Stack()
pdaStack.push("Z")
state = "q0"
print("Startzustand:", state, "\tLeerzustand Stack:", pdaStack.stackliste)
ergebnis = Akzeptor("aaaaabbbbb")
print("---------\nAkzeptiert?", ergebnis)