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Learning Python and I need help

Hey,

So I am taking a basic Python class and one of my assignments was to create a very simple calculator..

Btw, I am using Python 2.3 (As that's what the teacher wants us to use because of livewires)

It's very simple, but I am experiencing an error that I don't know how to fix (which is probably too simple for you guys to fix haha).. So I am getting this error on IDLE:

Quote:

Traceback (most recent call last):
File "C:/Python23/calculator", line 38, in -toplevel-
a.retry()
File "C:/Python23/calculator", line 32, in retry
Calculator.calc()
TypeError: unbound method calc() must be called with Calculator instance as first argument (got nothing instead)

I don't know how to fix it, I've tried multiple things and I couldn't get it to work.. Here's the code:

Code:

import sys



class Calculator(object):

    def calc(self):

        x = int(input("Please enter the first number: "))

        y = int(input("Please enter the second number: "))

        #op = Operator

        op = str.lower(raw_input(

              "Please enter what method you want to use ((A)ddition, (S)ubtraction, (M)ultiplication, (D)ivision) or type 'end' to quit: "))

        if op != "a"  and op != "s" and op != "m" and op != "d" and op != "end":

            exit = str.lower(raw_input("Are you sure you want to exit calculator (Yes or No)? "))

            if exit == "yes":

                sys.exit(0)

            else:

                calc()

        else:

            if op == "a":

                print ("\nThe result is: ", x, "+", y, "=", str(x+y))

    

            elif op == "s":

                print ("\nThe result is: ", x, "-", y, "=", str(x-y))



            elif op == "m":

                print ("\nThe result is: ", x, "*", y, "=", str(x*y))



            elif op == "d":

                print ("\nThe result is: ", x, "/", y, "=", str(float(x)/float(y)))



    def retry(self):

        confirm = str.lower(raw_input("Would you like to do another calculation (Yes or No)? "))

        if confirm == "yes":

            Calculator.calc()

        else:

            sys.exit(0)



a = Calculator()

a.calc()

a.retry()





raw_input("\nPress any key to exit.")

If you guys can help me on this one that would be great.. I am just curious on how to fix this small issue.

Re: Learning Python and I need help

Okay fixed the first error:

But I am getting another error if I choose "No" when it asks me to do another calculation:

Quote:

Traceback (most recent call last):
File "C:/Python23/calculator", line 41, in -toplevel-
a.retry()
File "C:/Python23/calculator", line 37, in retry
sys.exit(0)
SystemExit: 0

Here's the new code (I put what I changed in bold):

Code:

import sys







class Calculator(object):

    def calc(self):

        x = int(input("Please enter the first number: "))

        y = int(input("Please enter the second number: "))

        #op = Operator

        op = str.lower(raw_input(

            "Please enter what method you want to use ((A)ddition, (S)ubtraction, (M)ultiplication, (D)ivision) or type 'end' to quit: "))

        if op != "a"  and op != "s" and op != "m" and op != "d" and op != "end":

            exit = str.lower(raw_input("Are you sure you want to exit calculator (Yes or No)? "))

            if exit == "yes":

                sys.exit(0)

            else:

                calc()

        else:

            if op == "a":

                print ("\nThe result is: ", x, "+", y, "=", str(x+y))

    

            elif op == "s":

                print ("\nThe result is: ", x, "-", y, "=", str(x-y))



            elif op == "m":

                print ("\nThe result is: ", x, "*", y, "=", str(x*y))



            elif op == "d":

                print ("\nThe result is: ", x, "/", y, "=", str(float(x)/float(y)))



    def retry(self):

        confirm = str.lower(raw_input("Would you like to do another calculation (Yes or No)? "))

        b = Calculator()

        if confirm == "yes":

            b.calc()

        else:

            sys.exit(0)



a = Calculator()

a.calc()

a.retry()





raw_input("\nPress any key to exit.")

Re: Learning Python and I need help

In the retry() method,

Code:

Calculator.calc()

should be

Code:

self.calc()

EDIT: No need to create another instance of Calculator, as the existing instance is passed as the argument to both calc() and retry().

Re: Learning Python and I need help

Thanks marxian!

Ah good stuff! I changed the code quite a bit and now it's working like how I want it! :)

Code:

import sys



class Calculator(object):

    def quit_prompt(self):

            exit = str.lower(raw_input("Are you sure you want to exit calculator (Yes or No)? "))

            if exit == "yes":

                sys.exit()

            else:

                calc()



    def add(self, x, y):

        print "The result is: ", x, "+", y, "=", str(x+y)

    def subt(self, x, y):

        print "The result is: ", x, "-", y, "=", str(x-y)

    def mult(self, x, y):

        print "The result is: ", x, "*", y, "=", str(x*y)

    def div(self, x, y):

        print "The result is: ", x, "/", y, "=", str(float(x)/float(y))

        

    def calc(self):

        x = int(input("Please enter the first number: "))

        y = int(input("Please enter the second number: "))

        #op = Operator

        op = str.lower(raw_input(

            "Please enter what method you want to use ((A)ddition, (S)ubtraction, (M)ultiplication, (D)ivision) or type 'end' to quit: "))  

        while op != "end":

            if op == "a":

                self.add(x, y)

    

            if op == "s":

                self.subt(x, y)



            if op == "m":

                self.mult(x, y)

    

            if op == "d":

                self.div(x, y)

            self.retry()

            break

        



    def retry(self):

        confirm = str.lower(raw_input("\nWould you like to do another calculation (Yes or No)? "))

        if confirm == "yes":

            self.calc()

        else:

            pass



a = Calculator()

a.calc()



print "\nThank you for using the calculator!"

raw_input("\nPress any key to exit.")

Re: Learning Python and I need help

EDITED: Nvm, I solved the new issue by myself! Props to me! lol

Re: Learning Python and I need help

Great bandora. Python rules. Why not adjust it and add a gui and release it for your favorite device? Or are you unly looking to learn python syntax?

Re: Learning Python and I need help

Well I am taking a Python class, so all this is pretty much just for learning purposes.. And the edited post was about another code.. I am making a simple python game using pygame and livewires (it's my final), so far so good lol...

I absolutely love TMO on this matter! Like it's pretty much guaranteed you're gonna get helped developing anything! Thanks again! :)