Stack vs Array Direct Use Why We Need Stack Abstraction in DSA C - Interactive Comparison Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an array to use as a stack with size 5.

DSA C

int stack[[1]];

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A5

B0

C10

Dstack

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 as size causes no space for elements.

Using variable name instead of size inside brackets.

The stack array size must be 5 to hold 5 elements.

2fill in blank

medium

Complete the code to initialize the top of the stack to -1 (empty).

DSA C

int top = [1];

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A5

B-1

C1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting top to 0 means stack appears full at start.

Using positive numbers incorrectly.

Top is set to -1 to indicate the stack is empty initially.

3fill in blank

hard

Fix the error in the push function to correctly add an element to the stack.

DSA C

void push(int stack[], int *top, int value) {
    if (*top < 4) {
        *top = *top [1] 1;
        stack[*top] = value;
    }
}

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

A+

B*

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction causes overwriting previous elements.

Using multiplication or division is incorrect here.

We add 1 to top to move to the next free position before inserting.

4fill in blank

hard

Fill both blanks to correctly pop an element from the stack and update top.

DSA C

int pop(int stack[], int *top) {
    if (*top == [1]) {
        return -1; // stack empty
    }
    int value = stack[*top];
    *top = *top [2] 1;
    return value;
}

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

A-1

B0

C+

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Checking top == 0 means stack appears empty too early.

Incrementing top after pop is wrong.

Check if top is -1 (empty). Decrement top by 1 after popping.

5fill in blank

hard

Fill all three blanks to check if stack is full and print a message.

DSA C

if (*top [1] [2]) {
    printf("Stack is [3]\n");
}

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

A==

B4

Cfull

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than instead of equality.

Printing wrong message.

Stack is full when top equals 4 (last index). Print 'full' message.