WEBVTT

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so in the previous we talked
about the While loop and we had a very simple

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game that we modified to use a random now the problems we had with that

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code of course was that were only able
to have two guess’ in the code and

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the consequently it made the game very frustrating because unless you fluked it

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in which I tried three times and was
unable to do that, you wouldn’t be able to solve it

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so you won’t be able to win the game

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so the challenge I got the same code I pasted in a new Python file called

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challenge, and your challenge is to
modify the program below and to use a

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while loop to allow as many guesses as necessary
so you see obviously in the current code

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at the moment with only have two guess’ and that's it but
your gonna change all so the program

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now should let the player know where to guess
higher or lower and should put a message

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whether the guess is correct and the correct guess will terminate the program, now as an optional extra

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allow the player to quit by entering the number 0 before they guess

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so time to pause the video go away and see if you can figure this out, and of course were

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you want to create a while loop statement to do that

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and when you're ready to come back and
see the solution come back and will go through that

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so pause the video now, so hopefully you managed to get a
solution to that and to get it working

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so lets go through our proposed solution
now to see whether we can figure it out

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so what we need to do is we need to put
a while loop in here we need to get rid of all

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these extra bits of code that we no
longer need so were gonna leave the first part which

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is correct

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which is generating the random number and printing it out on the screen and what we're

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going to do now is instead of putting guess = int(input) input what we need to do is

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initialized that to 0 because if you recall in our
discussions with a while loop we need to

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pre-initialized that variable as we done in the for loop, a for loop doesn't need to but a while it

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does, so its going to be

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that can be initialised basically to any number, it has to be outside of valid
range again, if we got it in the valid

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range as you saw when I created in the
previous video then the while would not

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be started for the first time so making
it zero when its going to be OK

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and because the reason we know that it's not
a valid number is of course on line 15 we

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are getting a random number which starts on the
low range as one and in the highest ranges

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which is tent and therefore we know that we get a
number of 21 and 10 so guess has to be an invalid

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number, so to fix this now we need to change that to while loop so we
gonna

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and we are gonna put, and so again because guess is 0 this code will work on the first time we run it and

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will prompt for input which is correct
and then we still need to put some tests in here

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to check whether it's less than or greater than or put an else in there if you got it the first time, so were going to delete that, and get rid of this “you got it right

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the first time” so we’ve now gotta to check if guess is less than
the answer in other words I’ve typed in

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a number that is lower than the answers, so its gonna
say please guess higher, otherwise have typed in a

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number that's higher than the actual answer so the else comes in and says we need to guess lower, we need to take

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this next line actually out because we don't wanna input the

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code again what we really want to do is
wanna put an else there, and I should

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have change this code here to be an elif

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now the final else we longer need, so you can see now we are left with a while loop that start making sure

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that guess is not equal to answer as soon as
guess equals the loop is effectively going to end

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and so what happens is we do is guess = inputs so we are
getting the integer from the keyboard

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if the typed number is less than ours were gonna print a message please guess higher, else if guess is

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greater than answer, then we print the 
message please guess lower than else if it

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was not less and greater then in it means the we got it right, so print will done you guess it, and obviously if the

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code gets down to hear that's not
true it's gonna look back again until guess

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as equal to answer

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essentially as long as the guess doesn't
equal to answer the loop’s continues to

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request a new guess and checking the
answer and you can see now that the if

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statements are obviously a lot easier
because of taking something out we just

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checking for less then greater than we can let the player know to guess higher or lower or print when they get it right, so lets just run

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that and make sure that it does work, please guess a number between 1 and 10

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will try 5, please guess lower so 3 and that confused me for a moment because of course we're running the wrong

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program so I need to close that, we are
running the while program we created in

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the previous video, I need to right
click and run this first, click challenge

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will try again, 5 again please guess higher, try 7 days, please guess higher will try 8 well

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done you guess it, we got the number 8, and will just try again so lets try the number 9, guess lower, 1,5,6,7, well done you guessed it, we will try again

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10 please guess lower, 5 higher, 7, 8, 9, well done you guessed it, is clearly working now so lets also do the

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optional challenge and of course the
optional extra of this challenge is for 0 to

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break out of the loop and it's quite
simple to do after the guess where we are

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entering the number or getting the
number from the keyboard we put

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that should be equal to 0, two == and now if we run that, lets make sure that working, so if we put a 0, and there we go exits the loop, and just to make the app

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more interesting so if we close this down let's
make the highest number a 1000 now

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what you should be able to do, is you have
to guess the correct number within 10

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guesses, if looked at what I was doing
initially probably got an idea what I

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was doing especially from the
previous video and little bit in this

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video but there is a way of doing this so you can within 10 guesses no matter what the

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number is the, whatever the number ranges you should be
able to determine that within 10 guesses

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So I’m going to leave that Im not going to show you how to do that, see if you can figure

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that out but you will find out how and
why later in the course so that's it

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that's this video finished now and will
see you in the next one