"""File:     arithmetic2.py
   Purpose:  Carry out a series of basic arithmetic operations

   Run:      python arithmetic2.py

   Input:    Series of triples
             Value1
             Operation (+, -, *, /)
             Value2
             Operation = 'x' quits
   Output:   Results of Value1 Operation Value2
"""

def execute_op(val1, op, val2):
   if op == '+':
      return val1 + val2
   elif op == '-':
      return val1 - val2
   elif op == '*':
      return val1*val2
   elif op == '/':
      return val1/val2
   else:
      return None

#----------------------------------------------------------------------
# Program starts executing here
val1 = float(raw_input("Enter a number\n"))
op = raw_input("Enter an operation (+, -, *, /), x to quit\n")
val2 = float(raw_input("Enter a number\n"))
while op != 'x':
   result = execute_op(val1, op, val2)
   if result == None:
      print op, "isn't a valid operation"
   else:
      print val1, op, val2, "=", result
   val1 = float(raw_input("\nEnter a number\n"))
   op = raw_input("Enter an operation (+, -, *, /), x to quit\n")
   val2 = float(raw_input("Enter a number\n"))

print "Bye!"