📅 Date: Jan 6, 2026
🔥 Topic: Functions (Part 1): Definition & Syntax

🧩 Why Functions?

Until now, I was writing everything inside main(). It was getting messy. Functions allow us to break our code into smaller, reusable blocks.

Think of a function as a "Mini-Program" inside your program. You write it once, and you can call it a thousand times.

🏗️ The Anatomy of a Function

A function has 3 main parts:

  1. Return Type: What does it give back? (int, void, etc.)
  2. Function Name: What do we call it? (e.g., printMenu)
  3. Body: The code inside { }.
// Syntax
returnType functionName() {
    // Code to be executed
}

💻 Day 6 Code: My First Function

I created a simple function that prints a welcome message. I realized that the function must be defined before main (or declared) to work. 

#include <iostream>
using namespace std;

// Defining the Function
void sayHello() {
    cout << "-----------------------" << endl;
    cout << "Hello from a Function!" << endl;
    cout << "-----------------------" << endl;
}

int main() {
    cout << "Starting Main..." << endl;

    // Calling the Function
    sayHello();
    sayHello(); // Reusability!

    cout << "Ending Main..." << endl;
    return 0;
}

💭 Thoughts

The keyword void means the function returns nothing. It just does its job and finishes. This makes the main() function look so much cleaner!