Throw statement in PowerShell - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to throw an error with the message 'Invalid input'.

PowerShell

throw [1]

Drag options to blanks, or click blank then click option'

A'Invalid input'

BInvalid input

CError 'Invalid input'

DWrite-Error 'Invalid input'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put the message in quotes causes a syntax error.

Using Write-Error instead of throw does not stop script execution.

The throw statement requires a string message enclosed in quotes to throw an error with that message.

2fill in blank

medium

Complete the code to throw a custom error object with the message 'File not found'.

PowerShell

$error = New-Object System.Exception([1])
throw $error

Drag options to blanks, or click blank then click option'

A'File not found'

B[File not found]

CFile not found

D{File not found}

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the message causes an error.

Using brackets or braces instead of quotes is invalid.

The New-Object constructor expects a string message, so the message must be in quotes.

3fill in blank

hard

Fix the error in the code to correctly throw an error with the message 'Access denied'.

PowerShell

throw [1]

Drag options to blanks, or click blank then click option'

AAccess denied

BWrite-Error 'Access denied'

C[Access denied]

D'Access denied'

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving the message unquoted causes a syntax error.

Using Write-Error does not throw an exception.

The throw statement requires a string message in quotes. Without quotes, it causes a syntax error.

4fill in blank

hard

Fill both blanks to throw a new exception with the message 'Operation failed'.

PowerShell

throw New-Object System.[1]([2])

Drag options to blanks, or click blank then click option'

AException

B'Operation failed'

C'Operation succeeded'

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Using Error instead of Exception causes an error.

Not quoting the message causes a syntax error.

The correct class is Exception and the message must be a quoted string.

5fill in blank

hard

Fill all three blanks to throw a new System.Exception with a message stored in variable $msg.

PowerShell

$msg = 'Disk full'
throw New-Object System.[1]([2])

Drag options to blanks, or click blank then click option'

AException

B$msg

C'$msg'

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Putting $msg in quotes passes the literal string '$msg' instead of its value.

Using Error instead of Exception causes an error.

Use Exception class and pass the variable $msg without quotes to use its value.

Practice

1. What does the throw statement do in PowerShell?

easy

A. It stops the script and shows an error message.

B. It continues the script without any interruption.

C. It prints a warning but does not stop the script.

D. It pauses the script and waits for user input.

Solution

1. Step 1: Understand the purpose of throw

   The throw statement is used to stop script execution immediately and display an error message.

2. Step 2: Compare with other options

   Options B, C, and D describe behaviors that do not match throw. Only It stops the script and shows an error message. correctly describes stopping the script with an error.

3. Final Answer:

   It stops the script and shows an error message. -> Option A

4. Quick Check:

   throw stops script = A [OK]

Hint: Remember: throw always stops script with error [OK]

Common Mistakes:

• Thinking throw only shows a warning
• Confusing throw with Write-Host or Write-Warning
• Assuming throw pauses for input

2. Which of the following is the correct syntax to throw an error with the message "File not found" in PowerShell?

easy

A. throw -Message "File not found"

B. throw 'File not found'

C. throw File not found

D. throw(File not found)

Solution

1. Step 1: Check correct syntax for throw message

   PowerShell requires the error message to be a string, enclosed in quotes. Both single and double quotes work, but single quotes are common.

2. Step 2: Analyze each option

   throw -Message "File not found" is invalid (throw has no -Message parameter). throw(File not found) uses parentheses incorrectly. throw File not found misses quotes, causing syntax error. throw 'File not found' uses correct syntax.

3. Final Answer:

   throw 'File not found' -> Option B

4. Quick Check:

   throw 'message' syntax = D [OK]

Hint: Use quotes around error message with throw [OK]

Common Mistakes:

• Omitting quotes around the error message
• Using parentheses incorrectly with throw
• Confusing throw syntax with function call

3. What will be the output of this PowerShell script?

try {
  throw 'Error occurred'
  Write-Output 'This will not run'
} catch {
  Write-Output "Caught: $_"
}

medium

A. This will not run

B. Error occurred

C. No output

D. Caught: Error occurred

Solution

1. Step 1: Understand throw inside try block

   The throw stops execution inside try and passes control to catch with the error message.

2. Step 2: Check catch block output

   The catch block outputs "Caught: $_" where $_ contains the error message 'Error occurred'. So output is "Caught: Error occurred".

3. Final Answer:

   Caught: Error occurred -> Option D

4. Quick Check:

   throw in try triggers catch output = C [OK]

Hint: throw inside try triggers catch block output [OK]

Common Mistakes:

• Expecting code after throw to run
• Ignoring catch block output
• Confusing error message with direct output

4. Identify the error in this PowerShell script:

try {
  throw "Missing file"
} catch {
  Write-Output "Error: $error"
}

medium

A. The try block should not contain throw.

B. The throw statement is missing parentheses.

C. The catch block uses $error instead of $_ to get the error message.

D. Write-Output cannot be used inside catch.

Solution

1. Step 1: Review error variable usage in catch

   Inside catch, the automatic variable $_ holds the current error. $error is an array of all errors, not the current one.

2. Step 2: Identify correct variable for error message

   Using $error will output the entire error list, not the specific message. $_ is correct to get the thrown error message.

3. Final Answer:

   The catch block uses $error instead of $_ to get the error message. -> Option C

4. Quick Check:

   Use $_ in catch for error message = A [OK]

Hint: Use $_ in catch, not $error, for current error message [OK]

Common Mistakes:

• Using $error instead of $_ in catch
• Thinking throw needs parentheses
• Believing throw can't be inside try

5. You want to stop a script if a variable $filePath is empty or null, showing the message "File path is required". Which code snippet correctly uses throw to do this?

hard

A. if (-not $filePath) { throw 'File path is required' }

B. if ($filePath -eq $null) throw File path is required

C. throw 'File path is required' if ($filePath -eq '')

D. if ($filePath) { throw 'File path is required' }

Solution

1. Step 1: Check condition for empty or null variable

   Using -not $filePath correctly checks if $filePath is null, empty, or false.

2. Step 2: Verify throw syntax and condition placement

   if (-not $filePath) { throw 'File path is required' } uses correct if statement and throw with quoted message. if ($filePath -eq $null) throw File path is required misses quotes and may cause syntax error. throw 'File path is required' if ($filePath -eq '') has wrong syntax order. if ($filePath) { throw 'File path is required' } throws when $filePath exists, which is wrong.

3. Final Answer:

   if (-not $filePath) { throw 'File path is required' } -> Option A

4. Quick Check:

   Use if (-not var) { throw 'msg' } = B [OK]

Hint: Use if (-not $var) { throw 'msg' } to check empty/null [OK]

Common Mistakes:

• Forgetting quotes around error message
• Using throw before if condition
• Throwing error when variable is set