Stack Implementation Using Array in DSA C - Build from Scratch

Stack Implementation Using Array

📖 Scenario: You are building a simple stack data structure using an array in C. A stack works like a stack of plates: you add (push) plates on top and remove (pop) plates from the top only.This project will help you understand how to create a stack, keep track of its size, add items, and remove items using an array.

🎯 Goal: Build a stack using an array with basic operations: push and pop. You will create the array, set the stack size, add elements, and then remove elements, printing the stack state at the end.

📋 What You'll Learn

Create an integer array called stack with size 5

Create an integer variable called top and set it to -1 to track the top of the stack

Write a function push that adds an integer to the stack if there is space

Write a function pop that removes the top element from the stack if it is not empty

Push the numbers 10, 20, and 30 onto the stack

Pop one element from the stack

Print the current elements in the stack from bottom to top

💡 Why This Matters

🌍 Real World

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

💼 Career

Understanding stack implementation helps in software development, debugging, and working with low-level system programming.

1

Create the stack array and top variable

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

DSA C

# Create the stack array and top variable
// Your code here

Hint

Use int stack[5]; to create the array and int top = -1; to track the top.

2

Write the push function

Write a function called push that takes an integer value and adds it to stack if top is less than 4. Increase top by 1 and assign value to stack[top].

DSA C

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

// Write the push function below
// Your code here

Hint

Check if top is less than 4 before adding. Increase top then assign the value.

3

Write the pop function and push values

Write a function called pop that decreases top by 1 if top is not -1. Then, use push to add 10, 20, and 30 to the stack.

DSA C

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

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

// Write the pop function below
// Your code here

// Push 10, 20, 30 below
// Your code here

Hint

In pop, check if top is not -1 before decreasing it. Then call push three times with 10, 20, and 30.

4

Pop one element and print the stack

Call pop() once to remove the top element. Then use a for loop with i from 0 to top to print each element in stack[i] separated by spaces.

DSA C

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

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

void pop() {
    if (top != -1) {
        top--;
    }
}

int main() {
    push(10);
    push(20);
    push(30);
    
    // Pop one element
    // Your code here

    // Print stack elements
    // Your code here

    return 0;
}

Hint

Call pop() once. Then loop from 0 to top and print each stack[i] with a space.