Starting My Frontend Development Journey: Day 3 of #100DaysOfCode 💻🚀

Hey Dev Community! 👋

Continuing my #100DaysOfCode journey, today I deeply practiced all essential JavaScript Arithmetic Operators (+, -, *, /, %, **, ++, --) using real-world scenarios like shopping carts, grocery bills, game timers, and savings logic.

Here is a breakdown of what I built and learned today! 💡

💡 TL;DR:

• 
  Basic Arithmetic (+, -, *, /): Handles core logic like totals, discounts, and averages.


• 
  Modulo (%): Perfect for converting units (e.g., total seconds into hours/minutes/seconds).


• 
  Exponentiation (`):** Powers & exponential growth calculation (2 ** 5 = 32`).


• 
  Post vs Pre Operators (x++ vs ++x): Post uses old value first; Pre updates immediately.

🛒 1. Shopping Cart & Grocery Bill Logic

Practiced addition, subtraction, multiplication, division, and .toFixed() for financial calculations.

// Grocery Bill Calculation

const milk = 2 * 200;

const bread = 3 * 150;

const sugar = 1 * 180;



let subtotal = milk + bread + sugar;

let discount = (10 / 100) * subtotal;

const deliveryFee = 50;



let finalBill = subtotal - discount + deliveryFee;

let avgCost = subtotal / 3;



console.log("Subtotal: Rs.", subtotal);

console.log("Final Bill: Rs.", finalBill);

console.log("Average Cost Per Item Type: Rs.", avgCost.toFixed(2));

⏱️ 2. Game Playtime Converter (Modulo % & Division /)

Converted total raw game seconds (7485s) into Hours, Minutes, and Seconds using remainder arithmetic.

const totalSeconds = 7485;



// Extract Hours

let remainingAfterHours = totalSeconds % 3600;

let hours = (totalSeconds - remainingAfterHours) / 3600;



// Extract Minutes & Seconds

let remainingSeconds = remainingAfterHours % 60;

let minutes = (remainingAfterHours - remainingSeconds) / 60;



console.log(`Time: ${hours}h ${minutes}m ${remainingSeconds}s`);

// Output: Time: 2h 4m 45s

📈 3. Savings Growth with Exponentiation (**)

Calculated compound money doubling over time using the exponentiation operator.

let initialAmount = 10;

let multiplier = 2;

let years = 5;



// Formula: Initial * (Multiplier ^ Years)

let totalSavings = initialAmount * (multiplier ** years);

console.log("Total Savings after 5 years:", totalSavings); // Output: 320

⚡ 4. Increment (++) & Decrement (--) Operators

🔹 Post-Op (itemCount++, itemCount--)

Uses the current value first, then updates in the background.

let itemCount = 1;

let displayedQuantityAdd = itemCount++; // Displays 1, updates DB to 2

🔹 Pre-Op (++completedOrders, --activeOrders)

Updates the value immediately, then returns the result.

let completedOrders = 9;

let totalOrdersForBonus = ++completedOrders; // Immediately becomes 10

📝 Arithmetic Operators Quick Reference

📂 Source Code & Repository

Check out the full working code for all 5 exercises on GitHub:

🔗 GitHub Repository: https://github.com/CodeWithSehar/js-logic-building

🧠 Quick Quiz for You!

What will be the output of this JavaScript snippet? Drop your answer in the comments below! 👇

javascript

let x = 4;

let result = x++ + ++x;

console.log(result);