While loop only looping 3 times - python-3.x

Question

I'm trying to create a sum game where the problems are randomly generated. I'm using the random module to generate numbers and then asking for the user to input answers, then trying to compare user input to a variable that already contains the correct answer.
After 5 questions I want the while loop to break and 'end the game', but it's doing some strange things. It will loop 3 times then call a correct answer incorrect (See function CheckAnswer()) It's like my function to check user input against the correct answer isn't running, but I can't find where it's failing.
I'm pretty new to Python and this is the first project i'm attempting on my own. I didn't want it to be simple.
I've really just tried messing around with my functions and code to see if anything improves and it's worked for me until now.
point = 0
q_num = 0
def RandomNums():
rNum1 = random.randrange(51)
rNum2 = random.randrange(51)
return rNum1
return rNum2
def Add():
rNum1 = RandomNums()
rNum2 = RandomNums()
question = input("What is {} + {}?: ".format(rNum1, rNum2))
answer = rNum1 + rNum2
return question
print(answer)
return answer
#Check actual answer against user input
def CheckAnswer():
if question == answer:
point += 1
print("Correct! +1 Point!")
print(point)
else:
print("Wrong. Next question.")
time.sleep(1)
# Ask user to choose their operator
op = input("Which operator do you want to use (x, -, /, +)?: ").strip().lower()
if op == 'x':
while q_num < 5:
RandomNums()
Multiply()
question = Multiply()
answer = Multiply()
CheckAnswer()
q_num += 1
print(point)
elif op == '+':
while q_num < 5:
RandomNums()
Add()
question = Add()
answer = Add()
CheckAnswer()
q_num += 1
print(point)
else:
print("What!? That's not a choice!")
I expect that if I get the answer correct (on input) that I'll get the print statement inside my CheckAnswer() function and that 1 will be added to my 'point' variable. I also expect that my 'q_num' variable will increase by 1 regardless because I want the while loop to break at 5 questions, ending the game.
What I get when I run the program is I can input anything and it won't tell me anything, regardless of whether it's correct or not. The while loop will loop 3 times and say my answer is incorrect on the 4th loop. Then it seems to reset the loop and q_num count.

Answer 1

Several problems here, and first I strongly recommend taking a python course, or working through an online book. I worry that you're going to develop some very serious misconceptions that I already see in your code.
First off, and I don't know how to say this so that you'll absorb it, the computer executes instructions in order, one at a time. This is a hard lesson to learn, especially if you try to learn it after already playing around with code some!
I know, because I remember as a kid wanting something to work with BASIC for loops that makes no sense if you've properly absorbed this lesson, but that made perfect sense to me at the time.
In your code, the consequence of not absorbing this lesson properly are the multiple return statements in a function. Once the computer hits one return statement, it leaves the function. This means that stuff after the first return statement that's encountered doesn't happen.
So let's take a look at your Add function:
def Add():
rNum1 = RandomNums()
rNum2 = RandomNums()
question = input("What is {} + {}?: ".format(rNum1, rNum2))
answer = rNum1 + rNum2
return question
print(answer)
return answer
It's going to get two random numbers (we'll ignore the issues in RandomNums for the moment), then it's going to ask a question, take what the user did, put it in the local variable question, compute something for the local variable answer and then return the local variable question.
That's it. It's done then. It never does anything else.
This means that later in your program, when you say:
question = Add()
answer = Add()
What happens is that you ask the user two questions, and then set the global variable question to what the user said the first time, and set the global variable answer to what the user said the second time.
So your loop is really doing this:
RandomNums() # Compute two random numbers, return one, throw result away
Add() # Make a question, ask the user, throw the result away
question = Add() # Make a question, ask the user, store what they said
answer = Add() # Make a question, ask the user, store what they said
CheckAnswer() # Check if what the user said both times is the same, print message
q_num += 1 # increment loop number
print(point) # print point total
So your while loop wasn't running three times - it was running once, and in that one loop you were asking the user a question three times.
So you'd think then that something you could do is answer the same thing the last two times, and then you'd at least get the "correct answer" message. Unfortunately, you don't, because of another problem that's something slightly tricky about Python. What happens is this:
Which operator do you want to use (x, -, /, +)?: +
What is 40 + 31?: 3
What is 13 + 31?: 3
What is 2 + 9?: 3
Traceback (most recent call last):
File "/tmp/quiz.py", line 49, in <module>
CheckAnswer()
File "/tmp/quiz.py", line 24, in CheckAnswer
point += 1
UnboundLocalError: local variable 'point' referenced before assignment
What's happening here is that python thinks that point is a variable name that is local to the function CheckAnswer, when you of course want CheckAnswer to be modifying the global variable called point. Usually, python does the right thing with whether a variable should be global or local, (after all, it correctly deduced that you wanted to deal with the global answer and question) but += 1 looks like you're setting a new value (it's equivalent to point = point + 1), so python thought you meant a local variable called point. You can tell it otherwise by adding a global point statement to the top of CheckAnswer:
def CheckAnswer():
global point
if question == answer:
point += 1
print("Correct! +1 Point!")
print(point)
else:
print("Wrong. Next question.")
time.sleep(1)
Now when I play your quiz, this happens:
$ python /tmp/tst.py
Which operator do you want to use (x, -, /, +)?: +
What is 19 + 18?: 3
What is 4 + 39?: 3
What is 15 + 27?: 3
Correct! +1 Point!
1
1
What is 19 + 31?: 3
What is 21 + 47?: 4
What is 23 + 39?: 3
Wrong. Next question.
1
What is 45 + 12?: 2
What is 8 + 32?: 3
What is 28 + 16?: 3
Correct! +1 Point!
2
2
What is 23 + 0?: 0
What is 20 + 28?: 1
What is 0 + 49?: 2
Wrong. Next question.
2
What is 42 + 4?: 0
What is 27 + 18?: 1
What is 16 + 8?: 2
Wrong. Next question.
2
So that's a tiny improvement, and you can see that the loop is happening five times as expected.
Okay, so what about the problem you had before that you need to return two things, but the function stops at the first return statement?
What you can do is return something that in python is called a tuple, and then you can unpack it at the other end:
def RandomNums():
rNum1 = random.randrange(51)
rNum2 = random.randrange(51)
return (rNum1, rNum2) # return two things as a tuple
def Add():
(rNum1, rNum2) = RandomNums() # Unpack the tuple into two variables
question = input("What is {} + {}?: ".format(rNum1, rNum2))
answer = rNum1 + rNum2
return (question, answer) # return a tuple of question and answer
And then later:
elif op == '+':
while q_num < 5:
(question, answer) = Add()
CheckAnswer()
q_num += 1
print("Points are: {}".format(point))
So this almost works. Unfortunately, it says our answer is wrong every time!
That's because in python, strings and integers are different things. What you got from the user (question) will be the string '40' whereas the answer you computed will be the integer 40. So to properly compare them, you need to either turn answer into a string or turn question into an integer.
I chose in the code below to turn answer into a string, but you could take the other choice if you're okay with your program blowing up when the user enters something that isn't an integer. (My experience with users is that they'll start to enter swear words into your program after a bit, which naturally won't turn into integers). The function in python to turn most things into a string is str.
So here's the whole program now:
# in your post, you forgot these import statements
import time
import random
# set up global variables
point = 0
q_num = 0
def RandomNums():
rNum1 = random.randrange(51)
rNum2 = random.randrange(51)
return (rNum1, rNum2) # return a tuple
def Add():
(rNum1, rNum2) = RandomNums() # unpack tuple into two variables
question = input("What is {} + {}?: ".format(rNum1, rNum2))
answer = str(rNum1 + rNum2) # Note how answer is now a string
return (question, answer)
#Check actual answer against user input
def CheckAnswer():
global point # need this since we assign to point in this function
if question == answer:
point += 1
print("Correct! +1 Point!")
print(point)
else:
print("Wrong. Next question.")
time.sleep(1)
# Ask user to choose their operator
op = input("Which operator do you want to use (x, -, /, +)?: ").strip().lower()
if op == 'x':
while q_num < 5:
print("Not done yet, come back later")
break # Now the computer won't try anything below; break exits the while loop
(question, answer) = Multiply()
CheckAnswer()
q_num += 1
print("Points are: {}".format(point))
elif op == '+':
while q_num < 5:
(question, answer) = Add()
CheckAnswer()
q_num += 1
print("Points are: {}".format(point))
else:
print("What!? That's not a choice! (yet)")
Now go implement the rest of your quiz.
A small suggestion: for - and especially for /, you might want to have the two random numbers chosen be the second operand and the answer, instead of the two operands. For example:
def Divide():
(answer, rNum2) = RandomNums() # unpack tuple into two variables
product = rNum2 * answer # good thing answer isn't a string yet, or this wouldn't work
question = input("What is {} / {}?: ".format(product, rNum2))
answer = str(answer) # change answer to a string, now that we're done doing math
return (question, answer)