Array traversal in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print all elements of the array using a for loop.

C++

#include <iostream>

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    for (int i = 0; i < n; i++) {
        std::cout << arr[[1]] << " ";
    }
    return 0;
}

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

Ai

Bn

C0

Darr

Attempts:

3 left

💡 Hint

Common Mistakes

Using the array name instead of the index.

Using the size variable as the index.

The variable i is used as the index to access each element of the array during traversal.

2fill in blank

medium

Complete the code to calculate the sum of all elements in the array.

C++

#include <iostream>

int main() {
    int arr[] = {10, 20, 30, 40};
    int n = sizeof(arr) / sizeof(arr[0]);
    int sum = 0;
    for (int i = 0; i < n; i++) {
        sum += arr[[1]];
    }
    std::cout << sum << std::endl;
    return 0;
}

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An

Bsum

Ci

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Adding the size variable instead of the element.

Using the sum variable as an index.

The loop variable i is used to access each element to add it to sum.

3fill in blank

hard

Fix the error in the loop condition to correctly traverse the array.

C++

#include <iostream>

int main() {
    int arr[] = {5, 10, 15};
    int n = sizeof(arr) / sizeof(arr[0]);
    for (int i = 0; i [1] n; i++) {
        std::cout << arr[i] << " ";
    }
    return 0;
}

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A<

B<=

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= causes out-of-bounds access.

Using > or >= causes the loop to never run.

The loop should run while i is less than n to avoid going out of array bounds.

4fill in blank

hard

Fill both blanks to create a loop that prints elements at even indices only.

C++

#include <iostream>

int main() {
    int arr[] = {2, 4, 6, 8, 10, 12};
    int n = sizeof(arr) / sizeof(arr[0]);
    for (int i = [1]; i < n; i [2]) {
        std::cout << arr[i] << " ";
    }
    return 0;
}

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A0

Bi += 2

Ci++

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Starting at 1 instead of 0.

Using i++ increments by 1, not 2.

Start at index 0 and increase i by 2 each time to access even indices.

5fill in blank

hard

Fill all three blanks to create a loop that prints elements in reverse order.

C++

#include <iostream>

int main() {
    int arr[] = {3, 6, 9, 12, 15};
    int n = sizeof(arr) / sizeof(arr[0]);
    for (int i = [1]; i [2] 0; i [3]) {
        std::cout << arr[i] << " ";
    }
    return 0;
}

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An - 1

B>

C--i

D++i

Attempts:

3 left

💡 Hint

Common Mistakes

Starting at 0 instead of the last index.

Using ++i instead of --i to go backwards.

Start from the last index n - 1, loop while i is greater than 0, and decrement i each time.