Multi-dimensional arrays in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a 2D array of integers with 3 rows and 4 columns.

C++

int arr[3][[1]];

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A5

B3

C4

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing rows and columns sizes.

Using the wrong number for the second dimension.

The second dimension size is the number of columns, which is 4 here.

2fill in blank

medium

Complete the code to access the element in the second row and third column of a 2D array named 'matrix'.

C++

int value = matrix[[1]][2];

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A1

B2

C3

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 2 instead of 1 for the second row index.

Confusing row and column indices.

Array indices start at 0, so the second row is index 1.

3fill in blank

hard

Fix the error in the code to correctly initialize a 2D array with 2 rows and 3 columns.

C++

int grid[2][3] = {{ {1, 2, 3}, [1] }};

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A{4, 5, 6}

B(4, 5, 6)

C[4, 5, 6]

D4, 5, 6

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets or parentheses instead of curly braces.

Not enclosing the second row in braces.

Each row must be enclosed in braces {}. So the second row is {4, 5, 6}.

4fill in blank

hard

Fill both blanks to declare and initialize a 2D array named 'table' with 2 rows and 2 columns, containing values 1, 2, 3, 4.

C++

int table[[1]][[2]] = {{ {1, 2}, {3, 4} }};

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A2

B3

C4

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 or 4 instead of 2 for dimensions.

Mixing up rows and columns.

The array has 2 rows and 2 columns, so both dimensions are 2.

5fill in blank

hard

Fill all three blanks to create a nested loop that prints all elements of a 2D array 'data' with 3 rows and 2 columns.

C++

for (int i = 0; i < [1]; i++) {
    for (int j = 0; j < [2]; j++) {
        std::cout << data[i][j] << [3];
    }
    std::cout << std::endl;
}

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A3

B2

C" "

D"\n"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong loop limits.

Printing newline inside inner loop instead of space.

The outer loop runs 3 times for rows, inner loop 2 times for columns, and elements are separated by a space.