Lab 4: Guess My Number
Overview
In this lab, you will practice using while loops in
Python by implementing the classic game “Guess My Number”.
Be sure to read carefully! This lab writeup has lots of hints
and instructions to help you along the way.
Grading Criteria
To receive credit, each pair muust complete two Python (.py) files:
guess_number.py includes function definitions for Steps 1, 2, and 3.computer_guess.py includes function definitions for Steps 4 and 5.
Step 0: Getting started
In this and the following labs, we will be creating interactive programs
that require user input. PyCharm is an
IDE
that lets us write these types of programs in Python.
Open PyCharm and create a new project (by going to the File menu
and selecting New Project). Name it labs_150.
Accept the other defaults and click Create.
At this point you will have a new, empty project. Each project can
contain multiple Python files. To create a new Python file, you can
either choose New... under the File menu, or right click on the
project folder and select New.... Make sure you select New
Python File. Then you can type in a name for the file. Note that
you should not include .py on the end of the name;
PyCharm will add .py for you.
Step 1
For the first step, you will implement a basic version of the game.
Here is what a sample run of the program might look like:
Welcome to guess the number!
I will pick a number from 1-100, and you try to guess it.
I will tell you whether each guess is too low or too high.
...OK, I have picked a number.
Your guess? 50
50 is too low.
Your guess? 60
60 is too high.
Your guess? 65
65 is too high.
Your guess? 61
61 is too high.
Your guess? 55
55 is too high.
Your guess? 51
You got it! It took you 6 guesses.
Start by creating a file called guess_number.py and paste
the following code into it:
######################################
# Copyright (c) 2024 YOUR NAME(s) HERE
# CSCI 150, Spring 2023
# Lab 4: Guess My Number
######################################
import random
def main():
# Write your code here
# Call main() as the last thing in the file
main()
Update it with your name. Inside the main() function,
you should implement the game as illustrated above.
- Use
random.randint(1, 100) to pick a random number
between 1 and 100.
- Of course you will need a
while loop to keep
prompting the user for their guess. As the loop control variable,
you can use either the user’s guess itself, or you can create a
sentinel variable which starts as False and
becomes True once the user has correctly guessed the
number.
- As in the Collatz example in class, you will need to use a
separate counter variable to keep track of the number of guesses.
Step 2
Your game works now, but it has a problem:
Welcome to guess the number!
I will pick a number from 1-100, and you try to guess it.
I will tell you whether each guess is too low or too high.
...OK, I have picked a number.
Your guess? fifty
Traceback (most recent call last):
File "guess_number.py", line 33, in <module>
main()
File "guess_number.py", line 22, in main
guess = int(input("Your guess? "))
ValueError: invalid literal for int() with base 10: 'fifty'
If the user enters invalid input, the program will crash. We have
noted this problem before, but now that we know how to do repetition,
we can actually do something about it!
You should write a new function called input_guess(). Here is a
template you can use as a starting point; copy it into your file
(after import random and before def main():):
def input_guess() -> int:
# input_guess prompts the user for their guess, and keeps prompting
# until it is valid.
#
# Input: none
# Output: a valid guess (int)
# Keep prompting the user for their guess until they enter
# something valid
# FILL IN CODE HERE
# We only do this conversion at the end, once we know
# guess_str looks like an int
guess = int(guess_str)
# Finally, return the user's guess
return guess
Be sure that the comments and the def start all the way
over in the leftmost column of your file (do not put it inside
your main() function!).
If the user’s input is stored as a string in the
variable guess_str, you can check whether it is valid
using guess_str.isdigit(), which is a True or False value
telling you whether the string guess_str consists of all
digits or not.
Finally, replace the part of your main() function that
asks the user for their input with a call to your
new input_guess() function. That is, instead of
something like
guess = int(input("Your guess? "))
you should now have
Here’s what the output of your program might look like once you
complete this step:
Welcome to guess the number!
I will pick a number from 1-100, and you try to guess it.
I will tell you whether each guess is too low or too high.
...OK, I have picked a number.
Your guess? fifty
fifty is not a number. Try again.
Your guess? iuerhuheg
iuerhuheg is not a number. Try again.
Your guess? 20
20 is too low.
If you like, you may also modify input_guess() so that it
ensures the user’s guess is between 1 and 100, but this is not required.
Step 3
Since this game is so addictive, it’s inconvenient to re-run it every
time we want to play. In this step, you will modify the game so that
the user can keep playing multiple rounds until they decide to stop.
First, create a new function called run_game(). It will not have
any parameters nor will it return any value. Cut and paste the part
of main() that begins with generating the random number to
guess and ends with printing the number of guesses into this
new function. Then place a call to run_game() in main() where
that code used to be. Test the program and ensure it still works.
Next, write a new while loop in main(). Inside the loop,
call run_game() to play one round of the game. Then, ask the
user whether they wish to play again. The loop should end if the
user does not wish to play again. Here is what the output of
your program might look like once you get this to work:
Welcome to guess the number!
I will pick a number from 1-100, and you try to guess it.
I will tell you whether each guess is too low or too high.
...OK, I have picked a number.
Your guess? 50
50 is too low.
Your guess? 70
70 is too high.
Your guess? 60
60 is too high.
Your guess? 55
You got it! It took you 4 guesses.
Would you like to play again? (yes/no) yes
...OK, I have picked a number.
Your guess? 20
20 is too low.
Your guess? 80
80 is too high.
Your guess? 05
5 is too low.
Your guess? 50
50 is too high.
Your guess? 30
30 is too high.
Your guess? 25
25 is too high.
Your guess? 23
You got it! It took you 7 guesses.
Would you like to play again? (yes/no) no
Step 4
Finally, create a new file called computer_guess.py. Starting with
the template provided in step 1, implement the same game, but with
the roles reversed! That is, the human user picks a number, and the
computer tries to guess it.
Here is an example of what your program’s output might look like:
Welcome to guess the number! You pick a number from 1-100
and I will guess it. Please tell me whether my guesses are
"correct", "low", or "high".
Is your number 50? too high
Please respond with "correct", "low", or "high".
Is your number 50? erogiherg
Please respond with "correct", "low", or "high".
Is your number 50? high
Is your number 25? high
Is your number 12? low
Is your number 18? low
Is your number 21? high
Is your number 19? low
Is your number 20? correct
Yay! I win! It only took me 7 guesses.
Shall we play again? (yes/no) yes
Is your number 50? low
Is your number 75? low
Is your number 88? high
Is your number 81? high
Is your number 78? correct
Yay! I win! It only took me 5 guesses.
Shall we play again? (yes/no) no
A few hints:
- Be sure that your program responds appropriately if the user
inputs something unexpected, as in the example above.
- Your program should offer the option of playing again as long as
the user wants to continue playing.
- Write a
play_once() function that plays one round of the game.
- In
main(), call play_once() from within a while loop that
asks the user whether they wish to play again, much as we did
in Step 3.
- Do not use a random number to generate the computer’s guess.
The computer’s strategy should be systematic and deterministic.
Step 5:
Modify your strategy from Step 4 to ensure that the computer never
needs more than 7 guesses to win.