For loop in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this PowerShell for loop?

Consider the following PowerShell script:

for ($i = 1; $i -le 3; $i++) { Write-Output $i }

What will be the output when this script runs?

PowerShell

for ($i = 1; $i -le 3; $i++) { Write-Output $i }

A

3
2
1

B

0
1
2
3

C 1 2 3

D

1
2
3

💡 Hint

Remember the loop starts at 1 and runs while $i is less than or equal to 3.

The loop starts at 1 and increments by 1 until it reaches 3, outputting each number on its own line.

📝 Syntax

intermediate

Which option contains a syntax error in the PowerShell for loop?

Identify the option that will cause a syntax error when running the PowerShell for loop.

A for ($i=0; $i -lt 5; $i++) { Write-Output $i }

B for $i = 0; $i -lt 5; $i++ { Write-Output $i }

C for ($i = 0; $i -lt 5; $i++) { Write-Output $i }

D for ($i=0; $i -le 4; $i++) { Write-Output $i }

💡 Hint

Check the syntax of the for loop header carefully.

Option B is missing parentheses around the loop control statement, which is required in PowerShell.

🔧 Debug

advanced

Why does this PowerShell for loop not output anything?

Look at this script:

for ($i = 5; $i -lt 3; $i++) { Write-Output $i }

Why does it produce no output?

PowerShell

for ($i = 5; $i -lt 3; $i++) { Write-Output $i }

A Because the loop condition is false at the start, so the loop body never runs.

B Because the loop variable $i is not initialized.

C Because Write-Output is not the correct command to print in PowerShell.

D Because $i is incremented incorrectly causing an infinite loop.

💡 Hint

Check the initial value and the loop condition carefully.

The loop starts with $i = 5, but the condition $i -lt 3 (less than 3) is false, so the loop never runs.

🚀 Application

advanced

How many times will this PowerShell for loop run?

Given this script:

for ($i = 10; $i -ge 5; $i--) { Write-Output $i }

How many times does the loop execute?

PowerShell

for ($i = 10; $i -ge 5; $i--) { Write-Output $i }

A 6

B 5

C 4

D 7

💡 Hint

Count from 10 down to 5 inclusive.

The loop runs for $i = 10, 9, 8, 7, 6, 5 which is 6 times.

🧠 Conceptual

expert

What is the value of $sum after this PowerShell for loop?

Consider this script:

$sum = 0
for ($i = 1; $i -le 4; $i++) { $sum += $i }

What is the value of $sum after the loop finishes?

PowerShell

$sum = 0
for ($i = 1; $i -le 4; $i++) { $sum += $i }

A 4

B 9

C 10

D 0

💡 Hint

Add the numbers 1 through 4 together.

The loop adds 1 + 2 + 3 + 4 = 10 to $sum.

Practice

1.

What does a for loop in PowerShell do?

easy

A. Defines a function

B. Runs code only once

C. Stops the script immediately

D. Repeats a block of code a set number of times

Solution

1. Step 1: Understand the purpose of a for loop

   A for loop is designed to repeat code multiple times based on a condition.

2. Step 2: Compare options with the definition

   Only Repeats a block of code a set number of times correctly describes repeating code a set number of times.

3. Final Answer:

   Repeats a block of code a set number of times -> Option D

4. Quick Check:

   For loop = repeat code [OK]

Hint: For loops repeat code multiple times [OK]

Common Mistakes:

• Thinking for loop runs only once
• Confusing for loop with function definition
• Believing for loop stops script

2.

Which of the following is the correct syntax for a for loop in PowerShell?

for (init; condition; increment) { code }

easy

A. for ($i=0; $i -lt 5; $i++) { Write-Output $i }

B. for $i in 0..5 { Write-Output $i }

C. foreach ($i=0; $i -lt 5; $i++) { Write-Output $i }

D. while ($i=0; $i -lt 5; $i++) { Write-Output $i }

Solution

1. Step 1: Identify correct for loop syntax

   PowerShell for loops use parentheses with init; condition; increment separated by semicolons.

2. Step 2: Check each option

   for ($i=0; $i -lt 5; $i++) { Write-Output $i } matches correct syntax. A uses while keyword. B has invalid 'for $i in' syntax. C uses foreach keyword. [OK]

3. Final Answer:

   for ($i=0; $i -lt 5; $i++) { Write-Output $i } -> Option A

4. Quick Check:

   Correct for loop syntax = for ($i=0; $i -lt 5; $i++) { Write-Output $i } [OK]

Hint: For loop uses semicolons inside parentheses [OK]

Common Mistakes:

• Using foreach instead of for
• Using spaces instead of semicolons
• Confusing while loop syntax

3.

What will be the output of this PowerShell code?

for ($i=1; $i -le 3; $i++) { Write-Output ($i * 2) }

medium

A. 0 2 4

B. 1 2 3

C. 2 4 6

D. 3 6 9

Solution

1. Step 1: Understand loop iterations

   The loop runs with $i values 1, 2, and 3 because condition is $i -le 3.

2. Step 2: Calculate output for each iteration

   Output is $i * 2: 1*2=2, 2*2=4, 3*2=6.

3. Final Answer:

   2 4 6 -> Option C

4. Quick Check:

   Multiply each i by 2 = 2 4 6 [OK]

Hint: Multiply loop variable by 2 each iteration [OK]

Common Mistakes:

• Confusing loop range
• Multiplying after loop ends
• Printing loop variable instead of calculation

4.

Identify the error in this PowerShell for loop:

for (; $i < 5; $i++) { Write-Output $i }

medium

A. The increment operator '++' is invalid in PowerShell

B. The loop variable $i is not initialized

C. The condition uses '<' instead of '-lt'

D. The loop body is missing curly braces

Solution

1. Step 1: Check initialization syntax in for loop

   The initialization part is empty; $i needs to be initialized (e.g., $i=0).

2. Step 2: Verify other parts

   Increment '++' is valid, condition '<' works for numbers, braces are present.

3. Final Answer:

   The loop variable $i is not initialized -> Option B

4. Quick Check:

   Always initialize $i in for loop [OK]

Hint: Initialize loop variable in for loop [OK]

Common Mistakes:

• Forgetting to initialize loop variable
• Thinking '++' is invalid
• Using C-style operators like '<' in PowerShell

5.

You want to print only even numbers from 2 to 10 using a for loop in PowerShell. Which code snippet achieves this?

hard

A. for ($i=2; $i -le 10; $i+=2) { Write-Output $i }

B. for ($i=1; $i -lt 10; $i++) { if ($i % 2 -eq 0) { Write-Output $i } }

C. for ($i=2; $i -lt 10; $i++) { Write-Output $i }

D. for ($i=0; $i -le 10; $i+=3) { Write-Output $i }

Solution

1. Step 1: Understand the goal

   We want to print even numbers from 2 to 10 inclusive.

2. Step 2: Analyze each option

   for ($i=1; $i -lt 10; $i++) { if ($i % 2 -eq 0) { Write-Output $i } } goes to i<10 so prints 2,4,6,8 (misses 10). for ($i=2; $i -le 10; $i+=2) { Write-Output $i } starts at 2, increments by 2 up to 10: 2,4,6,8,10. for ($i=2; $i -lt 10; $i++) { Write-Output $i } prints 2-9 all numbers. for ($i=0; $i -le 10; $i+=3) { Write-Output $i } wrong start/step.

3. Final Answer:

   for ($i=2; $i -le 10; $i+=2) { Write-Output $i } -> Option A

4. Quick Check:

   Increment by 2 from 2 to 10 = even numbers [OK]

Hint: Increment by 2 starting at 2 for even numbers [OK]

Common Mistakes:

• Using wrong increment step
• Starting from 1 instead of 2
• Not filtering for even numbers