C Intro to Data Structures

C Intro to Data Structures – Understanding Data Structures in C

Data structures are essential for organizing and storing data efficiently in programs. In C programming, there are various types of data structures, each suited for specific tasks. Understanding these data structures helps improve program performance and efficiency.

🔹 What are Data Structures?

A data structure is a way of organizing and storing data so that it can be accessed and modified efficiently. There are several types of data structures, such as arrays, linked lists, stacks, queues, and trees, each with its own advantages and uses.

📝 Example 1: Basic Array

Arrays are a simple data structure used to store a collection of elements of the same type. Here’s an example of how you can declare and use an array in C.

#include <stdio.h>

int main() {
    int arr[5] = {1, 2, 3, 4, 5}; // Declaring and initializing an array

    for (int i = 0; i < 5; i++) {
        printf("Element at index %d: %d\n", i, arr[i]); // Accessing array elements
    }

    return 0;
}

🔹 Linked List

A linked list is a linear data structure where elements (called nodes) are stored in separate memory locations. Each node contains a data part and a reference (link) to the next node in the list.

📝 Example 2: Simple Linked List

This example shows a simple linked list with one node containing an integer value.

#include <stdio.h>
#include <stdlib.h>

struct Node {
    int data;
    struct Node* next;
};

int main() {
    struct Node* head = (struct Node*)malloc(sizeof(struct Node)); // Creating a new node
    head->data = 10; // Assigning value to the node
    head->next = NULL; // The next pointer is NULL, indicating the end of the list

    printf("Linked list element: %d\n", head->data); // Accessing node data

    free(head); // Freeing the memory allocated for the node

    return 0;
}

🔹 Stacks

A stack is a linear data structure that follows the LIFO (Last In, First Out) principle. The last element added to the stack is the first one to be removed.

📝 Example 3: Simple Stack

This example demonstrates a basic stack using an array.

#include <stdio.h>

#define MAX 5

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

void push(int value) {
    if (top == MAX - 1) {
        printf("Stack Overflow\n");
    } else {
        stack[++top] = value;
        printf("%d pushed to stack\n", value);
    }
}

int pop() {
    if (top == -1) {
        printf("Stack Underflow\n");
        return -1;
    } else {
        return stack[top--];
    }
}

int main() {
    push(10);
    push(20);
    printf("Popped: %d\n", pop());
    return 0;
}

🔹 Queues

A queue is a linear data structure that follows the FIFO (First In, First Out) principle. The first element added is the first one to be removed.

📝 Example 4: Simple Queue

This example shows a basic queue implementation using an array.

#include <stdio.h>

#define MAX 5

int queue[MAX];
int front = -1, rear = -1;

void enqueue(int value) {
    if (rear == MAX - 1) {
        printf("Queue Overflow\n");
    } else {
        if (front == -1) front = 0;
        queue[++rear] = value;
        printf("%d enqueued to queue\n", value);
    }
}

int dequeue() {
    if (front == -1 || front > rear) {
        printf("Queue Underflow\n");
        return -1;
    } else {
        return queue[front++];
    }
}

int main() {
    enqueue(10);
    enqueue(20);
    printf("Dequeued: %d\n", dequeue());
    return 0;
}

🎯 Key Takeaways

• Data structures are used to organize and manage data efficiently in programs.
• Common data structures in C include arrays, linked lists, stacks, and queues.
• Understanding data structures is crucial for optimizing performance and solving complex problems in programming.

📝 Practice Time!

Modify the examples to experiment with different data structures and operations. Try implementing additional data structures like trees or hash tables!