// Arithmetic operators
const a = 10, b = 3;
console.log(a + b);   // 13
console.log(a - b);   // 7
console.log(a * b);   // 30
console.log(a / b);   // 3.333...
console.log(a % b);   // 1 ← modulo: remainder of 10÷310÷3
console.log(2 ** 10); // 1024 ← exponentiation
 
// Modulo real-world uses
const hour = 14;
console.log(hour % 12 || 12); // 2 ← convert 24hr to 12hr
const isEven = n => n % 2 === 0;
console.log(isEven(4));  // true
console.log(isEven(7));  // false
 
// Assignment shorthand
let score = 100;
score += 25;   // score = score + 25 → 125125
score -= 10;   // 115
score *= 2;    // 230
score /= 5;    // 46
score **= 2;   // 2116
 
// Increment / decrement
let count = 0;
count++;       // 1 (post-increment: returns old value then increments)(post-increment: returns old value then increments)
++count;       // 2 (pre-increment: increments then returns new value)(pre-increment: increments then returns new value)
count--;       // 1

// Short-circuit evaluation
// && returns first falsy OR last value
console.log(true && 'hello');    // 'hello' (both truthy, returns last)(both truthy, returns last)
console.log(false && 'hello');   // false (stops at first falsy)(stops at first falsy)
console.log(null && doSomething()); // null (doSomething never called)(doSomething never called)
 
// || returns first truthy OR last value
console.log('user' || 'guest');  // 'user'
console.log('' || 'guest');      // 'guest' ('' is falsy)('' is falsy)
console.log(0 || 42);            // 42 (0 is falsy)(0 is falsy)
 
// ?? (nullish coalescing) — only triggers on null/undefined, NOT 0 or '') — only triggers on null/undefined, NOT 0 or ''
console.log(0 || 'default');     // 'default' (0 is falsy — often wrong!)(0 is falsy — often wrong!)
console.log(0 ?? 'default');     // 0 ← correct! 0 is a valid value0 is a valid value
console.log(null ?? 'default');  // 'default'
console.log(undefined ?? 'default'); // 'default'
 
// ?. (optional chaining) — safe property access) — safe property access
const user = { profile: { name: 'Alice' } };
const guest = null;
 
console.log(user?.profile?.name);    // 'Alice'
console.log(guest?.profile?.name);   // undefined (no error!)(no error!)
console.log(user?.address?.city);    // undefined (no error!)(no error!)
 
// Practical: default values with ??
const getDisplayName = (user) => user?.name ?? 'Anonymous';
console.log(getDisplayName({ name: 'Bob' }));  // 'Bob'
console.log(getDisplayName(null));             // 'Anonymous'

const account = {
  balance: 500,
  isFrozen: false,
  isVerified: true,
  dailyWithdrawnAmount: 200
};
const DAILY_LIMIT = 1000;
const withdrawalAmount = 300;
 
// Complex condition using multiple operators
const hasEnoughBalance = account.balance >= withdrawalAmount;
const withinDailyLimit = (account.dailyWithdrawnAmount + withdrawalAmount) <= DAILY_LIMIT;
const isAccountActive = !account.isFrozen && account.isVerified;
 
const canWithdraw = hasEnoughBalance && withinDailyLimit && isAccountActive;
 
if (canWithdraw) {
  const newBalance = account.balance - withdrawalAmount;
  console.log(`✅ Withdrawal approved. New balance: $${newBalance}`New balance: $${newBalance}`);
} else {
  const reason = !hasEnoughBalance ? 'Insufficient funds'
    : !withinDailyLimit ? 'Daily limit exceeded'
    : 'Account inactive';
  console.log(`❌ Denied: ${reason}`{reason}`);
}