Static vs dynamic arrays in Data Structures Theory - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the sentence to describe static arrays.

Data Structures Theory

A static array has a fixed size that is set at [1] and cannot be changed later.

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

Aruntime

Buser input

Ccompile time

Ddeletion

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing static arrays with dynamic arrays that can change size at runtime.

Static arrays have their size fixed at compile time, meaning the size is determined before the program runs and cannot be changed during execution.

2fill in blank

medium

Complete the sentence to describe dynamic arrays.

Data Structures Theory

Dynamic arrays can change their size during [1] to accommodate more or fewer elements.

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Aruntime

Bdebugging

Cinstallation

Dcompilation

Attempts:

3 left

💡 Hint

Common Mistakes

Thinking dynamic arrays have fixed size like static arrays.

Dynamic arrays can resize during runtime, which means while the program is running, they can grow or shrink as needed.

3fill in blank

hard

Fix the error in the statement about static arrays.

Data Structures Theory

Static arrays can [1] their size after creation.

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

Aincrease

Bdecrease

Cchange

Dnot change

Attempts:

3 left

💡 Hint

Common Mistakes

Assuming static arrays can grow or shrink like dynamic arrays.

Static arrays cannot change their size after creation; their size is fixed.

4fill in blank

hard

Fill both blanks to complete the sentence about dynamic arrays.

Data Structures Theory

Dynamic arrays usually [1] their size by [2] the current capacity when more space is needed.

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Adouble

Badding

Cmultiplying

Dreducing

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'adding' instead of 'multiplying' for resizing strategy.

Dynamic arrays often double their size by multiplying the current capacity to efficiently allocate more space.

5fill in blank

hard

Fill all three blanks to complete the dictionary comprehension about array types.

Data Structures Theory

array_info = [1]: [2] for [3] in ['static', 'dynamic']

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Aarr

B'fixed size' if arr == 'static' else 'resizable'

Carr.upper()

Attempts:

3 left

💡 Hint

Common Mistakes

Using the variable name as key without converting to uppercase.

Mixing up the conditional expression for values.

This comprehension creates a dictionary where keys are the uppercase array type names and values describe if they are fixed size or resizable.

Practice

1. Which of the following best describes a static array?

easy

A. An array that automatically resizes when elements are added

B. An array with a fixed size that cannot be changed after creation

C. An array that stores elements in linked nodes

D. An array that only stores strings

Solution

1. Step 1: Understand static array size property

   Static arrays have a fixed size set when created and cannot grow or shrink.

2. Step 2: Compare with other options

   Dynamic arrays resize automatically, linked nodes describe linked lists, and storing only strings is unrelated.

3. Final Answer:

   An array with a fixed size that cannot be changed after creation -> Option B

4. Quick Check:

   Static array = fixed size [OK]

Hint: Static arrays have fixed size, no resizing [OK]

Common Mistakes:

• Confusing static arrays with dynamic arrays
• Thinking static arrays can resize
• Mixing arrays with linked lists

2. Which syntax correctly declares a dynamic array in a typical programming language?

easy

A. int arr = 10;

B. int arr[10];

C. array arr = {1, 2, 3};

D. List<int> arr = new List<int>();

Solution

1. Step 1: Identify dynamic array syntax

   Dynamic arrays often use list or vector types that can resize, like List<int> in many languages.

2. Step 2: Check other options

   int arr[10]; declares a static array of fixed size 10, C is an array initialization but may be static, D is just an integer variable.

3. Final Answer:

   List<int> arr = new List<int>(); -> Option D

4. Quick Check:

   Dynamic array uses List or similar [OK]

Hint: Dynamic arrays use list or vector syntax [OK]

Common Mistakes:

• Using fixed size array syntax for dynamic arrays
• Confusing variable declaration with array declaration
• Assuming initialization equals dynamic resizing

3. Consider this pseudocode for a dynamic array:

arr = []
for i in range(5):
    arr.append(i)
print(len(arr))

What is the output?

medium

A. 0

B. 4

C. 5

D. Error

Solution

1. Step 1: Understand the loop and append operation

   The loop runs 5 times (i = 0 to 4), appending each i to the dynamic array.

2. Step 2: Calculate final length of array

   After 5 appends, the array length is 5.

3. Final Answer:

   5 -> Option C

4. Quick Check:

   Appending 5 items results in length 5 [OK]

Hint: Count loop iterations for append count [OK]

Common Mistakes:

• Counting from 1 instead of 0
• Assuming length is last index
• Thinking append fails without pre-sizing

4. What is the main issue with this code snippet using a static array?

arr = new int[3]
arr[0] = 10
arr[1] = 20
arr[2] = 30
arr[3] = 40

medium

A. Index out of bounds error at arr[3]

B. Array size is dynamic, so no error

C. Array elements are not initialized

D. No issue, code runs fine

Solution

1. Step 1: Check array size and index usage

   The array size is 3, so valid indices are 0, 1, 2 only.

2. Step 2: Identify error at arr[3]

   Accessing arr[3] exceeds the array bounds, causing an error.

3. Final Answer:

   Index out of bounds error at arr[3] -> Option A

4. Quick Check:

   Static array index must be within size [OK]

Hint: Static arrays have fixed max index size-1 [OK]

Common Mistakes:

• Assuming arr[3] is valid index
• Thinking arrays auto-expand
• Ignoring zero-based indexing

5. You need to store an unknown number of user inputs that can grow over time. Which array type is best and why?

hard

A. Dynamic array, because it can resize automatically

B. Static array, because it uses less memory

C. Static array, because it has faster access

D. Dynamic array, because it uses linked nodes

Solution

1. Step 1: Analyze requirement for unknown and growing size

   Since the number of inputs is unknown and can grow, resizing is needed.

2. Step 2: Choose array type based on resizing ability

   Dynamic arrays can resize automatically, making them suitable for this case.

3. Final Answer:

   Dynamic array, because it can resize automatically -> Option A

4. Quick Check:

   Unknown size needs dynamic array [OK]

Hint: Use dynamic arrays for unknown or growing sizes [OK]

Common Mistakes:

• Choosing static arrays for unknown size
• Confusing faster access with resizing ability
• Thinking dynamic arrays use linked nodes