Your First Program

Let's write some real Quartz programs. We'll start simple and progressively build more interesting examples.

Hello, World!

Create a file called hello.qz:

// hello.qz - The classic first program
import system.io as io

io.println("Hello, World!")

Run it:

quartz hello.qz

Output:

Hello, World!

Congratulations! Let's break down what happened:

• // comment — Comments start with //
• import system.io as io — Import the I/O module with alias io
• io.println("...") — Print a line to standard output

Variables and Types

Quartz uses let for variable declarations:

import system.io as io

// Integers
let age = 25
let year = 2024

// Floating-point numbers
let pi = 3.14159
let temperature = -40.5

// Strings
let name = "Quartz"
let greeting = "Hello, " + name + "!"

// Booleans
let isAwesome = true
let isBoring = false

io.println(greeting)
io.println("Age: " + age)
io.println("Pi: " + pi)

User Input

Read input from the user:

import system.io as io

io.print("What is your name? ")
let name = io.readLine()

io.print("How old are you? ")
let ageStr = io.readLine()
let age = int(ageStr)

io.println("Hello, " + name + "!")
io.println("Next year you'll be " + (age + 1) + " years old.")

Defining Functions

Functions are defined with fn:

import system.io as io

// Simple function
fn greet(name) {
io.println("Hello, " + name + "!")
}

// Function with return value
fn add(a, b) {
return a + b
}

// Use the functions
greet("World")
io.println("2 + 3 = " + add(2, 3))

Number Guessing Game

Here's a complete program that puts it all together:

// guess.qz - A number guessing game
import system.io as io
import system.math as math

class GuessingGame {
constructor(maxNumber) {
self.maxNumber = maxNumber
self.secretNumber = math.randint(1, maxNumber)
self.attempts = 0
self.won = false
}

fn makeGuess(guess) {
self.attempts = self.attempts + 1

if (guess < self.secretNumber) {
return "Too low!"
} else if (guess > self.secretNumber) {
return "Too high!"
} else {
self.won = true
return "Correct!"
}
}

fn play() {
io.println("=== Number Guessing Game ===")
io.println("I'm thinking of a number between 1 and " + self.maxNumber)
io.println("")

while (!self.won) {
io.print("Your guess: ")
let input = io.readLine()
let guess = int(input)

let result = self.makeGuess(guess)
io.println(result)
}

io.println("")
io.println("You won in " + self.attempts + " attempts!")
}
}

// Start the game
let game = GuessingGame(100)
game.play()

Execution Modes

Quartz offers two execution modes:

Interpreter Mode (Default)

quartz yourprogram.qz

Direct execution, great for development and debugging.

Bytecode Mode

quartz -c yourprogram.qz

Compiles to bytecode first, faster execution for larger programs.

Pre-compile Bytecode

# Compile to .qzb file
quartz -b yourprogram.qz

# Run compiled bytecode
quartz yourprogram.qzb