Check if Stack is Empty or Full in DSA C - Build from Scratch

Check if Stack is Empty or Full

📖 Scenario: Imagine you are managing a stack of books on a shelf. You want to know if the shelf is empty or completely full before adding or removing books.

🎯 Goal: You will create a simple stack using an array and write code to check if the stack is empty or full.

📋 What You'll Learn

Create an integer array called stack with size 5

Create an integer variable called top initialized to -1

Create an integer variable called max_size set to 5

Write a function isEmpty that returns 1 if the stack is empty, else 0

Write a function isFull that returns 1 if the stack is full, else 0

Print the results of isEmpty() and isFull()

💡 Why This Matters

🌍 Real World

Stacks are used in many places like undo features in apps, browser history, and managing tasks.

💼 Career

Understanding stack operations is important for software development, debugging, and working with system internals.

1

Create the stack array and top variable

Create an integer array called stack with size 5 and an integer variable called top initialized to -1.

DSA C

int stack[5];
int top = -1;
// Your code here

Hint

The stack is an array of size 5. The top variable keeps track of the last filled position, starting at -1 when empty.

2

Add max_size variable

Add an integer variable called max_size and set it to 5.

DSA C

int stack[5];
int top = -1;
int max_size = 5;
// Your code here

Hint

The max_size variable holds the maximum number of items the stack can hold.

3

Write isEmpty and isFull functions

Write a function isEmpty that returns 1 if top is -1, else 0. Write a function isFull that returns 1 if top equals max_size - 1, else 0.

DSA C

int stack[5];
int top = -1;
int max_size = 5;

int isEmpty() {
    // Your code here
}

int isFull() {
    // Your code here
}

Hint

The stack is empty if top is -1. It is full if top is one less than max_size.

4

Print if stack is empty or full

Print the results of isEmpty() and isFull() using printf.

DSA C

int stack[5];
int top = -1;
int max_size = 5;

int isEmpty() {
    if (top == -1) {
        return 1;
    } else {
        return 0;
    }
}

int isFull() {
    if (top == max_size - 1) {
        return 1;
    } else {
        return 0;
    }
}

// Print if stack is empty or full
// Your code here

Hint

Use printf to show the results of isEmpty() and isFull(). Since top is -1, the stack is empty and not full.