Aapka Pehla Rust Program

Har Rust program ka execution main naam ke function mein shuru hota hai — yeh non-negotiable hai, JavaScript ya Python ke bar-aks jahan code bas top-to-bottom chal sakta hai. println! ek macro hai (! par dhyan dein), function nahi, isi liye yeh aapko yahan har lesson mein nazar aayega.

Compiling sab se pehle hoti hai

Jab aap run dabate hain, rustc ek bhi line execute karne se pehle aapki poori file ko ek binary mein compile kar deta hai. Agar kahin bhi type error hai, borrow-checker violation hai, ya sirf ek syntax mistake bhi hai, to kuch bhi nahi chalta — aapko output ke bajaye compile error milta hai. Rust ke compiler ki shuhrat strict hone ki hai, lekin yehi strictness hai jo aapka code waqai execute hone se pehle bugs ki poori categories ko pakar leti hai.

Comments

Comments zyadatar C-family languages ki tarah kaam karte hain: line mein // ke baad jo bhi likha ho use bilkul ignore kar diya jaata hai, aur yeh sirf isliye hote hain taake baad mein code parhne wale log samajh sakein ke kuch is tarah kyun likha gaya hai.

Khud chala kar dekho

Yeh raha ek chhota program jisme ek comment aur do println! calls hain. Neeche dikhaya gaya output waqai execute kar ke nikala gaya hai — text badal kar khud bhi example ke neeche button se chala kar dekhein.

// This is a comment - Rust ignores it
fn main() {
    println!("Hello, World!");
    println!("Welcome to Rust.");
}

Hello, World!
Welcome to Rust.

Aage: variables aur mutability — Rust immutability ko default kaise banata hai, opt-in nahi.