If-elseif-else statements in PowerShell - Mini Project: Build & Apply

If-elseif-else statements

📖 Scenario: You are creating a simple script to check the temperature and give advice on what to wear. This is like asking a friend, "Is it cold, warm, or hot outside?" and then deciding what clothes to wear based on that.

🎯 Goal: Build a PowerShell script that uses if, elseif, and else statements to check a temperature value and print the right clothing advice.

📋 What You'll Learn

Create a variable called temperature with a specific number value.

Create a variable called coldThreshold with a number value.

Use if, elseif, and else statements to compare temperature with coldThreshold and another threshold.

Print the correct advice message based on the temperature.

💡 Why This Matters

🌍 Real World

Scripts like this help automate decisions based on data, such as adjusting settings or sending alerts depending on conditions.

💼 Career

Understanding conditional statements is essential for scripting tasks in IT, system administration, and automation roles.

1

Set the temperature value

Create a variable called temperature and set it to 15.

PowerShell

# Create a variable called temperature and set it to 15
# Your code here

Hint

Use $temperature = 15 to create the variable.

2

Set the cold temperature threshold

Create a variable called coldThreshold and set it to 10.

PowerShell

$temperature = 15
# Create a variable called coldThreshold and set it to 10
# Your code here

Hint

Use $coldThreshold = 10 to create the variable.

3

Write the if-elseif-else statements

Write an if statement to check if temperature is less than coldThreshold. Then add an elseif to check if temperature is less than 25. Use else for all other cases. Inside each block, assign a string message to a variable called advice as follows:
- If cold: "Wear a jacket"
- Elseif warm: "Wear a t-shirt"
- Else: "Wear shorts"

PowerShell

$temperature = 15
$coldThreshold = 10
# Write if-elseif-else statements to set advice based on temperature
# Your code here

Hint

Use if ($temperature -lt $coldThreshold) for the cold check, then elseif ($temperature -lt 25) for warm, and else for hot.

4

Print the clothing advice

Print the value of the advice variable using Write-Output.

PowerShell

$temperature = 15
$coldThreshold = 10
if ($temperature -lt $coldThreshold) {
    $advice = "Wear a jacket"
} elseif ($temperature -lt 25) {
    $advice = "Wear a t-shirt"
} else {
    $advice = "Wear shorts"
}
# Print the advice variable
# Your code here

Hint

Use Write-Output $advice to print the message.

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