Day 7 Functions
Function ek reusable block of code hai. Ek baar likho, baar baar use karo. Code organize karne ka sabse important tarika.
Function Declaration
Traditional way to declare a function.
// Function declare karna
function greet(name) {
return "Hello, " + name + "!";
}
// Function call karna
console.log(greet("Zohaib")); // Hello, Zohaib!
console.log(greet("Ali")); // Hello, Ali!
// Multiple parameters
function add(a, b) {
return a + b;
}
console.log(add(5, 3)); // 8
Arrow Functions (=>)
Modern, concise way to write functions. ES6 mein aaya.
// Regular function
function square(n) {
return n * n;
}
// Arrow function — same kaam
const square2 = (n) => {
return n * n;
};
// Even shorter (1 line)
const square3 = n => n * n;
console.log(square3(5)); // 25
// Multiple params
const multiply = (a, b) => a * b;
console.log(multiply(4, 6)); // 24
Default Parameters
Agar parameter na do to default value use ho.
function greet(name = "Guest", greeting = "Hello") {
return `${greeting}, ${name}!`;
}
console.log(greet()); // Hello, Guest!
console.log(greet("Zohaib")); // Hello, Zohaib!
console.log(greet("Ali", "Assalam")); // Assalam, Ali!
🎯 Practice Challenge
Calculator function banao jo 4 operations kare: add, subtract, multiply, divide. Test karo.