My if loop is taking effect even when it should not

user_16340123 0
Viewed 49

I am making a random number guessing program where users try to guess a number between 1 and 100 while receiving whether they were higher or lower. one of the stipulations was that there must be a function to quit the program upon the user entering Q or q so I formatted my loop as such:

$RandomNumber = Get-Random -Minimum 1 -Maximum 101
write-output $RandomNumber
$GuessNumber = 0
While ($RandomNumber -ne $Guess)
{
    $Guess = Read-Host -Prompt 'Guess a number between 1 and 100 Or enter Q to quit'
    if ($Guess -eq 'q' -or 'Q')
    {
        Write-output "Thank you for playing"
        BREAK
    }
    if ($Guess -gt 100 -or $Guess -le 1)
    {
        Write-Output 'Invalid Input please enter a number between 1 and 100'

    }
    if ($Guess -le $RandomNumber)
    {
        Write-output 'Your number is lower than the hidden number please guess again'
        $GuessNumber = $GuessNumber +1
    }
    if ($Guess -gt $RandomNumber)
    {
        Write-output 'Your number is higher than the hidden number please guess again'
        $GuessNumber = $GuessNumber +1
    }
    if ($Guess -eq $RandomNumber)
    {
        $GuessNumber = $GuessNumber +1
        Write-output 'Congratulations you guessed the number in' $GuessNumber 'tries'
    }
}

the issue I run into is even when the input is equal to 10 for example it still outputs "Thank you for playing" meaning that if loop has taken effect. I am not sure why this occurs as I'm new to powershell and a reasoning for this happening would be helpful

if-statement powershell loops
3 Answers

Replace

if ($Guess -eq 'q' -or 'Q')

with

if ($Guess -eq 'q' -or $Guess -eq 'Q')
user_17530730

The condition is wrong. $Guess -eq 'q' -or 'Q' returns true always, it should be $Guess -eq 'q' -or $Guess -eq 'Q'.

user_87389950

Your error partially comes from -or 'Q' which evaluates to $true always:

$false -or 'somestring' # => True

And it's also worth noting, -eq is case insensitive ('q' -eq 'Q' is $true).
The other error comes from comparing a string with an integer. The output from Read-Host is System.String in this case:

'50' -gt 100 # => True
'50' -lt 100 # => False

On the other hand, you could make your code more readable using a switch statement. For input validation you could use a recursive script block to make sure its always right (between 1 and 100 or Q). To break the outer while loop you can use a labeled break.

$RandomNumber = Get-Random -Minimum 1 -Maximum 101

$validation = {
    $choice = Read-Host 'Guess a number between 1 and 100 Or enter Q to quit'
    if($choice -notmatch '^([1-9][0-9]?|100|q)$') {
        Write-Warning 'Invalid Input, try again.'
        return & $validation
    }
    $choice
}

$attempts = 0

:outer while($true) {
    $choice = & $validation
    if($choice -eq 'q') {
        # End the Game
        'Thanks for Playing'
        break
    }

    $attempts++

    switch([int]$choice) {
        {$_ -gt $RandomNumber} {
            "$_ was greater than hidden number"
            break
        }
        {$_ -lt $RandomNumber} {
            "$_ was lower than hidden number"
            break
        }
        default {
            "You guessed right after $attempts tries, Congratulations!"
            break outer
        }
    }
}
user_153395440
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