Array size and bounds in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an array of 5 integers.

C++

int arr[[1]];

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

A-1

B10

C0

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using zero or negative numbers as array size causes errors.

Forgetting to specify the size inside the brackets.

The number inside the square brackets specifies the size of the array. Here, 5 means the array can hold 5 integers.

2fill in blank

medium

Complete the code to access the third element of the array.

C++

int value = arr[[1]];

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A2

B1

C3

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 instead of 2 for the third element index.

Confusing 1-based indexing with 0-based indexing.

Array indexing in C++ starts at 0, so the third element is at index 2.

3fill in blank

hard

Fix the error in the code to prevent out-of-bounds access.

C++

for (int i = 0; i < [1]; i++) {
    cout << arr[i] << " ";
}

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

A5

B6

C10

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using a loop limit greater than the array size causes out-of-bounds errors.

Using <= instead of < in the loop condition.

The array size is 5, so the loop should run while i is less than 5 to avoid accessing invalid elements.

4fill in blank

hard

Fill both blanks to create a dictionary that maps array indices to their values for elements greater than 10.

C++

std::map<int, int> result = {
    { [1], arr[[2]] }
};

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

A2

B3

C1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using different indices for key and value.

Using an index outside the array bounds.

We use the index 2 for both the key and to access the value in the array.

5fill in blank

hard

Fill all three blanks to create a loop that sums all elements in the array.

C++

int sum = 0;
for (int [1] = 0; [2] < [3]; [1]++) {
    sum += arr[[1]];
}

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

Ai

C5

Dn

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in the loop header.

Using a loop limit greater than the array size.

The variable i is used as the loop counter, and the loop runs while i is less than 5, the array size.