Array Insertion at End in DSA C - Practice Problems & Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output after inserting an element at the end?

Consider the following C code that inserts an element at the end of an array. What will be printed after insertion?

DSA C

int main() {
    int arr[5] = {1, 2, 3, 4};
    int size = 4;
    int capacity = 5;
    int element = 10;

    if (size < capacity) {
        arr[size] = element;
        size++;
    }

    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    return 0;
}

A 1 2 3 4

B 1 2 3 4 0

C 10 1 2 3 4

D 1 2 3 4 10

💡 Hint

Think about how the element is added and how the size changes.

The element 10 is added at index 4 (the end), and size is incremented to 5. The loop prints all 5 elements.

❓ Predict Output

intermediate

What happens if we insert beyond array capacity?

What will be the output of this C code snippet?

DSA C

int main() {
    int arr[3] = {5, 6, 7};
    int size = 3;
    int capacity = 3;
    int element = 9;

    if (size < capacity) {
        arr[size] = element;
        size++;
    }

    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    return 0;
}

A 5 6 7

B 5 6 7 9

C 9 5 6 7

D 5 6 7 0

💡 Hint

Check the condition before insertion carefully.

Since size equals capacity, the insertion does not happen. The array remains unchanged with 3 elements.

🔧 Debug

advanced

Why does this insertion code cause unexpected output?

Identify the problem in this code that inserts an element at the end of an array and prints it.

DSA C

int main() {
    int arr[4] = {1, 2, 3};
    int size = 3;
    int capacity = 4;
    int element = 8;

    arr[size] = element;
    // Missing size increment here

    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    return 0;
}

A Output: 1 2 3

B Output: 1 2 3 8

C Output: 1 2 3 0

D Runtime error due to out of bounds

💡 Hint

Check if the size variable is updated after insertion.

The element is assigned at arr[3], but size is not incremented, so the loop prints only first 3 elements.

❓ Predict Output

advanced

What is the output after multiple insertions at the end?

Given the following code, what will be printed?

DSA C

int main() {
    int arr[6] = {2, 4, 6};
    int size = 3;
    int capacity = 6;
    int elements_to_add[3] = {8, 10, 12};

    for (int i = 0; i < 3; i++) {
        if (size < capacity) {
            arr[size] = elements_to_add[i];
            size++;
        }
    }

    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    return 0;
}

A 2 4 6 8 10

B 2 4 6 8 10 12

C 2 4 6 0 0 0

D 8 10 12 2 4 6

💡 Hint

Look at how the loop adds elements and updates size.

All three elements 8, 10, 12 are added at the end, size becomes 6, and all elements print.

🧠 Conceptual

expert

What is the main limitation of inserting at the end of a static array?

Why can inserting an element at the end of a static array fail or be limited?

A Because the array automatically resizes causing slow insertion

B Because elements must be shifted to insert at the end

C Because the array size is fixed and cannot grow beyond its capacity

D Because inserting at the end requires sorting the array

💡 Hint

Think about the difference between static and dynamic arrays.

Static arrays have fixed size; once full, no more elements can be added without creating a new array.