class RPNCalculator(object):
def __init__(self):
self.calcEngine = CalculatorEngine()
#given a single reverse polish expression do an evaluation
def eval(self, line):
#implicit assumption being made here that the user will put spaces between the operators, operands
words = line.split(" ")
for item in words:
if item in '+-*/':
self.calcEngine.doTextOp(item)
else:
self.calcEngine.pushOperand(int(item))
#once done with all the computations, return whatever is right on top
return self.calcEngine.currentOperand()
def run (self):
while True:
line = raw_input("type an expression please\n")
if len(line) == 0: break
print self.eval(line)
def __init__(self):
self.calcEngine = CalculatorEngine()
