Array Traversal Patterns in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

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

DSA C

int arr[] = {1, 2, 3, 4, 5};
int n = 5;
for (int i = 0; i [1] n; i++) {
    printf("%d ", arr[i]);
}

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

A<=

B<

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= causes out-of-bounds access.

Using > or >= will not enter the loop.

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

2fill in blank

medium

Complete the code to traverse the array backwards and print elements.

DSA C

int arr[] = {10, 20, 30, 40, 50};
int n = 5;
for (int i = n - 1; i [1] 0; i--) {
    printf("%d ", arr[i]);
}

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

A<=

B>

C>=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using > excludes the first element at index 0.

Using < or <= will not work for backward traversal.

The loop should continue while i is greater than or equal to 0 to include the first element.

3fill in blank

hard

Fix the error in the code to correctly print every second element starting from the first.

DSA C

int arr[] = {5, 10, 15, 20, 25, 30};
int n = 6;
for (int i = 0; i [1] n; i += 2) {
    printf("%d ", arr[i]);
}

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

A<

B<=

C>=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= causes out-of-bounds access.

Using > or >= will not enter the loop.

The loop should run while i is less than n to avoid accessing out-of-bounds elements.

4fill in blank

hard

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

DSA C

int arr[] = {2, 4, 6, 8, 10, 12};
int n = 6;
for (int i = [1]; i [2] n; i += 2) {
    printf("%d ", arr[i]);
}

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

A1

B0

C<

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Starting at 0 prints even indices.

Using <= causes out-of-bounds access.

Start from index 1 (first odd index) and continue while i is less than n.

5fill in blank

hard

Fill all three blanks to create a loop that prints elements divisible by 3.

DSA C

int arr[] = {3, 5, 6, 7, 9, 12};
int n = 6;
for (int i = 0; i [1] n; i++) {
    if (arr[i] [2] 3 == 0) {
        printf("%d ", arr[[3]]);
    }
}

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

A<

B%

Ci

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= causes out-of-bounds access.

Using / instead of % for divisibility.

Printing arr[i+1] or wrong index.

Loop while i < n, check remainder with %, and print arr[i].