If-elseif-else statements in PowerShell - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if a number is positive.

PowerShell

if ($number [1] 0) { Write-Output "Positive" }

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

A-gt

B-ne

C-eq

D-lt

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-lt' which means less than, so it would check for negative numbers.

Using '-eq' which checks for equality, not greater than.

The operator '-gt' means 'greater than', so it checks if $number is greater than 0.

2fill in blank

medium

Complete the code to check if a number is zero.

PowerShell

if ($number -gt 0) { Write-Output "Positive" } elseif ($number [1] 0) { Write-Output "Zero" }

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

A-ne

B-lt

C-ge

D-eq

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-lt' or '-ge' which check less than or greater or equal, not equality.

Using '-ne' which means not equal, the opposite of what is needed.

The operator '-eq' means 'equals', so it checks if $number is exactly zero.

3fill in blank

hard

Fix the error in the else statement syntax.

PowerShell

if ($score -ge 90) { Write-Output "A" } elseif ($score -ge 80) { Write-Output "B" } else[1]Write-Output "F" }

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

Aelse {

Bthen {

C {

Delseif {

Attempts:

3 left

💡 Hint

Common Mistakes

Adding 'then' after else, which is not valid in PowerShell.

Writing 'elseif' instead of 'else' for the final block.

In PowerShell, 'else' must be followed by a space and then a block starting with '{'. No extra keywords like 'then' are used.

4fill in blank

hard

Fill both blanks to complete the if-elseif structure checking temperature.

PowerShell

if ($temp [1] 30) { Write-Output "Hot" } elseif ($temp [2] 15) { Write-Output "Warm" } else { Write-Output "Cold" }

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

A-gt

B-lt

C-ge

D-le

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-ge' or '-le' which include equality and may change logic.

Swapping the operators and confusing hot and warm conditions.

The first condition checks if temperature is greater than 30 (hot). The second checks if temperature is less than 15 (cold). Otherwise, it's warm.

5fill in blank

hard

Fill all three blanks to create a dictionary with keys as uppercase words and values as their lengths if length is greater than 3.

PowerShell

foreach ($word in $words) { if (($word.Length [1] 3) [2] $true)) { $dict[[3]] = $word.Length } }

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

A-gt

B-and

C$word.ToUpper()

D-lt

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-lt' instead of '-gt' which reverses the condition.

Using '-or' instead of '-and' which changes logic.

Not converting the word to uppercase for the dictionary key.

The condition checks if word length is greater than 3 and uses '-and' to combine conditions if needed. The dictionary key is the uppercase version of the word.

Practice

1. What does an if-elseif-else statement do in PowerShell?

easy

A. It chooses which code to run based on conditions.

B. It repeats code multiple times.

C. It stores data in variables.

D. It defines a function.

Solution

1. Step 1: Identify the purpose of if-elseif-else

   An if-elseif-else statement checks conditions and runs code based on which condition is true. This matches "It chooses which code to run based on conditions."

2. Final Answer:

   It chooses which code to run based on conditions. -> Option A

3. Quick Check:

   if-elseif-else controls flow by conditions = B [OK]

Hint: If it picks code based on true/false, it's if-elseif-else [OK]

Common Mistakes:

• Confusing if-elseif-else with loops
• Thinking it stores data
• Mixing it up with function definitions

2. Which of the following is the correct syntax to start an if statement in PowerShell?

easy

A. if $x == 5 then { }

B. if ( $x -eq 5 ) { }

C. if $x = 5 { }

D. if $x equals 5 { }

Solution

1. Step 1: Recall PowerShell if syntax and verify options

   PowerShell uses if (condition) { code } with -eq for equality check. "if ( $x -eq 5 ) { }" uses correct parentheses, -eq operator, and braces. Others use wrong operators or keywords.

2. Final Answer:

   if ( $x -eq 5 ) { } -> Option B

3. Quick Check:

   PowerShell if: parens + -eq = A [OK]

Hint: Use parentheses and -eq for conditions in if [OK]

Common Mistakes:

• Using == instead of -eq
• Omitting parentheses
• Using = for comparison

3. What will this PowerShell code output?

 $num = 7
if ($num -lt 5) {
  'Less than 5'
} elseif ($num -eq 7) {
  'Equal to 7'
} else {
  'Other'
}

medium

A. Equal to 7

B. No output

C. Other

D. Less than 5

Solution

1. Step 1: Trace code execution step-by-step

   $num is 7, ($num -lt 5) is false. ($num -eq 7) is true, outputs 'Equal to 7'.

2. Final Answer:

   Equal to 7 -> Option A

3. Quick Check:

   7 -eq 7 triggers elseif = D [OK]

Hint: Check conditions top to bottom, first true runs [OK]

Common Mistakes:

• Choosing first if block without checking condition
• Ignoring elseif block
• Assuming else runs always

4. Find the error in this PowerShell snippet:

if $value -gt 10 {
  'Greater than 10'
} elseif ($value -eq 10) {
  'Equal to 10'
} else {
  'Less than 10'
}

medium

A. Braces {} are not allowed

B. Using -gt instead of >

C. Missing else keyword

D. Missing parentheses around first if condition

Solution

1. Step 1: Check syntax and identify the error

   PowerShell requires parentheses around the condition in if statements. The first if lacks them: "if $value -gt 10 {" should be "if ($value -gt 10) {". Matches "Missing parentheses around first if condition".

2. Final Answer:

   Missing parentheses around first if condition -> Option D

3. Quick Check:

   All if conditions need parentheses = A [OK]

Hint: Always put conditions inside parentheses in if [OK]

Common Mistakes:

• Omitting parentheses in if
• Confusing -gt with > (both valid but -gt preferred)
• Forgetting else keyword

5. You want to write a script that prints:
- 'Cold' if temperature is below 10,
- 'Warm' if temperature is between 10 and 25 inclusive,
- 'Hot' if temperature is above 25.
Which if-elseif-else structure correctly implements this?

hard

A. if ($temp -lt 10) { 'Cold' } elseif ($temp -ge 25) { 'Hot' } else { 'Warm' }

B. if ($temp -le 10) { 'Cold' } elseif ($temp -lt 25) { 'Warm' } else { 'Hot' }

C. if ($temp -lt 10) { 'Cold' } elseif ($temp -le 25) { 'Warm' } else { 'Hot' }

D. if ($temp -gt 25) { 'Hot' } elseif ($temp -gt 10) { 'Warm' } else { 'Cold' }

Solution

1. Step 1: Analyze temperature ranges and verify conditions

   Cold: below 10, Warm: 10-25 inclusive, Hot: above 25. "if ($temp -lt 10) { 'Cold' } elseif ($temp -le 25) { 'Warm' } else { 'Hot' }": <10=Cold, <=25=Warm (10-25), else Hot. Matches exactly.

2. Final Answer:

   if ($temp -lt 10) { 'Cold' } elseif ($temp -le 25) { 'Warm' } else { 'Hot' } -> Option C

3. Quick Check:

   Ranges covered correctly = C [OK]

Hint: Order conditions from smallest to largest range [OK]

Common Mistakes:

• Mixing up less than and less or equal
• Wrong order causing wrong output
• Overlapping or missing ranges