Guess the number game optimization (user creates n

Question

I am very new to programming so I decided to start with Python about 4 or 5 days ago. I came across a challenge that asked for me to create a "Guess the number" game. After completion, the "hard challenge" was to create a guess the number game that the user creates the number and the computer (AI) guesses.

So far I have come up with this and it works, but it could be better and I'll explain.

from random import randint

print ("In this program you will enter a number between 1 - 100."
       "\nAfter the computer will try to guess your number!")

number = 0

while number < 1 or number >100:
    number = int(input("\n\nEnter a number for the computer to guess: "))
    if number > 100:
        print ("Number must be lower than or equal to 100!")
    if number < 1:
        print ("Number must be greater than or equal to 1!")

guess = randint(1, 100)

print ("The computer takes a guess...", guess)

while guess != number:
    if guess > number:
        guess -= 1
        guess = randint(1, guess)
    else:
        guess += 1
        guess = randint(guess, 100)
    print ("The computer takes a guess...", guess)

print ("The computer guessed", guess, "and it was correct!")

This is what happened on my last run:

Enter a number for the computer to guess: 78

The computer takes a guess... 74

The computer takes a guess... 89

The computer takes a guess... 55

The computer takes a guess... 78

The computer guessed 78 and it was correct!

Notice that it works, however when the computer guessed 74, it then guessed a higher number to 89. The number is too high so the computer guesses a lower number, however the number chosen was 55. Is there a way that I can have the computer guess a number that is lower than 89, but higher than 74? Would this require additional variables or more complex if, elif, else statements?

Thank you Ryan Haining

I used the code from your reply and altered it slightly so the guess is always random. If you see this, let me know if this is the best way to do so.

from random import randint

def computer_guess(num):
    low = 1
    high = 100
    # This will make the computer's first guess random
    guess = randint(1,100)
    while guess != num:
        print("The computer takes a guess...", guess)
        if guess > num:
            high = guess
        elif guess < num:
            low = guess + 1
        # having the next guess be after the elif statement
        # will allow for the random guess to take place
        # instead of the first guess being 50 each time
        # or whatever the outcome of your low+high division
        guess = (low+high)//2    

    print("The computer guessed", guess, "and it was correct!")


def main():
    num = int(input("Enter a number: "))
    if num < 1 or num > 100:
        print("Must be in range [1, 100]")
    else:
        computer_guess(num)

if __name__ == '__main__':
    main()

Answer 1

This is how I went about mine...

     __author__ = 'Ghengis Yan'

     print("\t This is the age of the computer")
     print("\n The computer should impress us... the Man")

     import random

     #User chooses the number
     the_number = int(input("Human Choose a number between 0 and 100 "))
     tries = 1
     computer = random.randint(0,100)
     # User choose again loop
     while the_number > 100:
         the_number = int(input("I thought Humans are smarter than that... \nRetype the number... "))
     if the_number <= 100:
         print("Good")

     # Guessing Loop
     while computer != the_number:
         if computer > the_number:
             print(computer, "lower... Mr. Computer")
         else:
             print(computer, "higher... Mr. Computer")
         computer = int(random.randint(0,100))
         tries += 1

     print("Computer Congratulations... You beat the human! The Number was ", the_number)
     print("It only took a computer such as yourself", tries, "tries to guess it right...          pathetic")
     input("\nPress the enter key to exit.")

Answer 2

what you are looking for is the classic binary search algorithm

def computer_guess(num):
    low = 1
    high = 100
    guess = 50
    while guess != num:
        guess = (low+high)//2
        print("The computer takes a guess...", guess)
        if guess > num:
            high = guess
        elif guess < num:
            low = guess + 1

    print("The computer guessed", guess, "and it was correct!")


def main():
    num = int(input("Enter a number: "))
    if num < 1 or num > 100:
        print("Must be in range [1, 100]")
    else:
        computer_guess(num)

if __name__ == '__main__':
    main()

The algorithm works by selecting a low and high limit to start with (in your case low=1 and high=100). It then checks the midpoint between them.

If the midpoint is less than number, the midpoint becomes the new lower bound. If the midpoint is higher, it becomes the new upper bound. After doing this a new midpoint is generated between the upper and lower bound.

To illustrate an example let's say you're looking for 82.

Here's a sample run

Enter a number: 82
The computer takes a guess... 50
The computer takes a guess... 75
The computer takes a guess... 88
The computer takes a guess... 82
The computer guessed 82 and it was correct!

So what's happening here in each step?

1. low = 1, high = 100 => guess = 50 50 < 82 so low = 51
2. low = 51, high = 100 => guess = 75 75 < 82 so low = 76
3. low = 76, high = 100 => guess = 88 88 > 82 so high = 88
4. low = 76, high = 88 => guess = 82 82 == 82 and we're done.

Note that the time complexity of this is O(lg(N))

Answer 3

If you use the stuff in the chapter (guessing this is from the Dawson book) you can do it like this.

import random
#program allows computer to guess my number
#initial values
user_input1=int(input("Enter number between 1 and 100: "))
tries=1
compguess=random.randint(1, 100)

#guessing loop
while compguess != user_input1:
    if compguess > user_input1:
        print("Lower Guess")
        compguess=random.randint(1, 100)
        print(compguess)
    elif compguess < user_input1:
        print("Higher Guess")
        compguess=random.randint(1, 100)
        print(compguess)

        tries += 1 #to have program add up amount of tries it takes place it in the while block

print("Good job Computer! You guessed it! The number was,", user_input1, \
      " and it only took you", tries, " tries!")

Answer 4

Try this:

import random


player = int(input("tap any number: "))
comp = random.randint(1, 100)
print(comp)

comp_down = 1
comp_up = 100

raw_input("Press Enter to continue...")


while comp != player:
   if comp > player:
    comp_up = comp - 1
    comp = random.randint(comp_down, comp_up)
    print(comp)
   if comp < player:
    comp_down = comp + 1
    comp = random.randint(comp_down, comp_up)
    print(comp)
   if comp == player:
       break