Assignment operators in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this PowerShell script using assignment operators?

Consider the following script. What will be the value of $a after execution?

PowerShell

$a = 10
$a += 5
$a *= 2
$a -= 4
$a

A 22

B 26

C 32

D 20

💡 Hint

Remember to apply each assignment operator step-by-step.

Start with $a = 10. Then $a += 5 makes $a 15. Next $a *= 2 makes $a 30. Finally $a -= 4 makes $a 26.

💻 Command Output

intermediate

What is the output of this script using string assignment operators?

What will be the value of $str after running this script?

PowerShell

$str = 'Hello'
$str += ' World'
$str += '!'

A Hello World!

B HelloWorld!

C Hello World !

D Hello+ World+!

💡 Hint

The += operator appends strings in PowerShell.

The += operator adds the string on the right to the existing string on the left without extra spaces.

📝 Syntax

advanced

Which option will cause a syntax error in PowerShell assignment?

Identify the option that will cause a syntax error when run in PowerShell.

A $a = 1; $a -= 1

B $y = 10; $y *= 2

C $x = 5; $x += 3

D $z = 7; $z + = 4

💡 Hint

Look carefully at the spacing and operator usage.

Option D uses '+ =' which is not a valid assignment operator in PowerShell and causes a syntax error.

🚀 Application

advanced

What is the value of $count after this loop with assignment operators?

Given this script, what is the final value of $count?

PowerShell

$count = 0
for ($i = 1; $i -le 5; $i++) {
  $count += $i
  if ($i % 2 -eq 0) {
    $count -= 1
  }
}
$count

A 13

B 14

C 15

D 10

💡 Hint

Add $i each time, but subtract 1 when $i is even.

Sum 1+2+3+4+5=15. Subtract 1 for i=2 and i=4 (two times), so 15-2=13. But careful: the subtraction happens inside the loop after adding i. The final count is 13.

🧠 Conceptual

expert

Which assignment operator will cause an error when used with a $null variable in PowerShell?

Assuming $var is $null, which assignment operation will cause a runtime error?

PowerShell

$var = $null
# Which operation causes error?

A $var += 5

B $var -= 3

C $var /= $null

D $var = 10

💡 Hint

Think about how PowerShell treats $null with arithmetic operators.

Dividing by $null causes an error because $null is treated as zero in the denominator, causing division by zero. Adding or subtracting treats $null as zero.

Practice

1. What does the += operator do in PowerShell?

easy

A. Subtracts the right value from the variable

B. Adds the right value to the variable and updates it

C. Assigns a new value without changing the old one

D. Divides the variable by the right value

Solution

1. Step 1: Understand the meaning of +=

   The += operator adds the value on the right to the current value of the variable.

2. Step 2: Recognize it updates the variable

   After addition, the variable stores the new sum, replacing the old value.

3. Final Answer:

   Adds the right value to the variable and updates it -> Option B

4. Quick Check:

   += means add and assign [OK]

Hint: Think: plus equals means add then save [OK]

Common Mistakes:

• Confusing += with simple assignment =
• Thinking it subtracts or divides
• Assuming it only adds without updating

2. Which of the following is the correct syntax to multiply a variable $x by 5 and update it in PowerShell?

easy

A. $x *= 5

B. $x =* 5

C. $x = *5

D. $x = 5*

Solution

1. Step 1: Recall the multiplication assignment operator

   In PowerShell, *= multiplies the variable by the right value and updates it.

2. Step 2: Check syntax correctness

   $x *= 5 uses $x *= 5, which is the correct syntax for multiplication assignment.

3. Final Answer:

   $x *= 5 -> Option A

4. Quick Check:

   Use *= for multiply and assign [OK]

Hint: Use operator symbol before = for combined assignment [OK]

Common Mistakes:

• Placing = before * incorrectly
• Adding spaces that break syntax
• Using invalid operator combinations

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

$count = 10
$count -= 3
$count += 2
Write-Output $count

medium

A. 5

B. 12

C. 7

D. 9

Solution

1. Step 1: Calculate subtraction assignment

   Starting with $count = 10, $count -= 3 subtracts 3, so $count becomes 7.

2. Step 2: Calculate addition assignment

   Then $count += 2 adds 2, updating $count to 9.

3. Final Answer:

   9 -> Option D

4. Quick Check:

   10 - 3 + 2 = 9 [OK]

Hint: Perform each assignment step by step [OK]

Common Mistakes:

• Adding before subtracting mentally
• Mixing up += and -= effects
• Ignoring update after each operation

4. Identify the error in this PowerShell code:

$value = 8
$value +== 2
Write-Output $value

medium

A. Syntax error due to invalid operator +==

B. No error, output will be 10

C. Runtime error because $value is not initialized

D. Output will be 8 because += does not change value

Solution

1. Step 1: Check the operator used

   The operator +== is not valid in PowerShell; the correct operator for addition assignment is +=.

2. Step 2: Understand the error impact

   This causes a syntax error, so the script will not run and output nothing.

3. Final Answer:

   Syntax error due to invalid operator +== -> Option A

4. Quick Check:

   Use +=, not +== [OK]

Hint: Check operator symbols carefully for typos [OK]

Common Mistakes:

• Typing double equals after plus
• Confusing comparison == with assignment operators
• Assuming += and +== are same

5. You want to concatenate the string "World" to variable $greeting which initially holds "Hello ". Which PowerShell statement correctly updates $greeting using an assignment operator?

hard

A. $greeting =+ "World"

B. $greeting =- "World"

C. $greeting += "World"

D. $greeting = "World" +

Solution

1. Step 1: Identify string concatenation operator

   In PowerShell, += adds the right string to the existing string variable.

2. Step 2: Validate correct syntax

   $greeting += "World" uses $greeting += "World", which appends "World" to "Hello ".

3. Final Answer:

   $greeting += "World" -> Option C

4. Quick Check:

   Use += to append strings [OK]

Hint: Use += to add strings to variables [OK]

Common Mistakes:

• Using =+ which is invalid
• Placing + after string incorrectly
• Using -= which subtracts, not concatenates