Stack IsFull

What is the "Is Full" Operation?

The Is Full operation checks whether a stack has reached its maximum capacity. This is particularly relevant for fixed-size stack implementations (arrays) rather than dynamic implementations (linked lists).

How It Works

Returns true if the stack cannot accept more elements.
Returns false if the stack can accept more elements.
For dynamic stacks (no fixed size), this operation typically always returns false.
Often used with Push operations to prevent stack overflow.

Time and Space Complexity

Here's the time and space complexity analysis for stack operations:

Fixed-size Stack:
- Time Complexity: O(1)
- Space Complexity: O(1)
Dynamic Stack:
- Time Complexity: O(1)
- Space Complexity: O(1)

Practical Example

Consider a stack with maximum capacity of 3 elements:

Stack: [ ]

isFull() → false

Stack: [5, 3]

isFull() → false

Stack: [7, 3, 5]

isFull() → true

Common Use Cases

Preventing stack overflow in memory-constrained systems.
Implementing bounded buffers or fixed-size caches.
Memory management in embedded systems.
Validating stack capacity before push operations

The Is Full operation is crucial when working with fixed-size stacks to prevent overflow errors. While not needed for dynamically-sized stacks, it's an essential safety check in many system-level implementations.

Visualize the LIFO (Last In, First Out) principle

Stack Visualization

Stack is empty

Capacity: 0/5

Stack is empty

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Stack Push & Pop Implementation

// Stack Implementation with isFull Operation in JavaScript
class Stack {
  constructor(maxSize = 5) {
    this.items = [];
    this.top = -1;
    this.MAX_SIZE = maxSize;
  }

  // Push operation with isFull check
  push(element) {
    if (this.isFull()) {
      console.log("Stack Overflow - Cannot push to full stack");
      return;
    }
    this.items[++this.top] = element;
    console.log(`Pushed: ${element}`);
  }

  // Pop operation
  pop() {
    if (this.isEmpty()) {
      console.log("Stack Underflow - Cannot pop from empty stack");
      return -1;
    }
    return this.items[this.top--];
  }

  // Check if stack is full
  isFull() {
    const full = this.top === this.MAX_SIZE - 1;
    console.log(`Stack is ${full ? "full" : "not full"}`);
    return full;
  }

  // Check if stack is empty
  isEmpty() {
    return this.top === -1;
  }

  // Display stack
  display() {
    console.log("Current Stack:", this.items.slice(0, this.top + 1));
  }
}

// Usage
const stack = new Stack(3); // Small stack for demonstration

console.log("Initial checks:");
stack.isFull();  // false
stack.isEmpty(); // true

stack.push(10);
stack.push(20);
stack.push(30);
stack.display();
stack.isFull();  // true

// Try to push to full stack
stack.push(40);  // Will show overflow message