## Stack Implementation using Arrays # We know arrays as Lists in python, but we will use Array word only. Dont confuse. ### Covers - ## Insert, Delete, Display class Stack(object): """docstring for Stack""" def __init__(self, limit, array = []): self.array = array self.limit = limit self.top = None self.size = len(self.array) self.set_top() self.pprint() def set_top(self): if self.array == []: self.top = None else: self.top = self.array[-1] def is_full(self): return self.size == self.limit def is_empty(self): return self.size == 0 def push(self, value): if self.size == self.limit: print "Stack Overflow" else: self.array.append(value) self.set_top() self.size += 1 self.pprint() def pop(self): if self.size == 0: print "Stack Underflow" else: print "Removing the item " + str(self.top) self.array.pop() self.set_top() self.size -= 1 self.pprint() def pprint(self): # could have used self.array.reverse() for the same thing if self.is_empty == True: print "Stack Empty" else: print "-------------> Top <------------" i= 0 while i < len(self.array): i+=1 print "| ^" + str(self.array[i*-1]) + " |" print "================================" ## Sample Implementation # >>> s=Stack(3,[31,32,89]) # -------------> Top <------------ # | ^89 | # | ^32 | # | ^31 | # ================================ # >>> # ................. Removing Some mid Part # >>> s.pop() # Removing the item 31 # -------------> Top <------------ # ================================ # >>> s.pop() # Stack Underflow # >>> # >>> # >>> s.pop() # Stack Underflow # >>> # >>> # >>> s.push(21) # -------------> Top <------------ # | ^21 | # ================================ # >>> s.push(24) # -------------> Top <------------ # | ^24 | # | ^21 | # ================================ # >>> s.push(29) # -------------> Top <------------ # | ^29 | # | ^24 | # | ^21 | # ================================ # >>> s.push(32) # Stack Overflow # Stack Overflow