Day 3: Functions

Functions are the building blocks of Rust programs. Let's master them!

What You'll Learn

• Function syntax and parameters
• Return types with ->
• Expressions vs statements
• Implicit returns

Function Syntax

fn function_name(param1: Type1, param2: Type2) -> ReturnType {
    // function body
}

Expressions vs Statements

fn add(a: i32, b: i32) -> i32 {
    a + b    // expression - no semicolon, this is returned
}

fn add_with_return(a: i32, b: i32) -> i32 {
    return a + b;  // explicit return (less idiomatic)
}

The Task

Convert Celsius to Fahrenheit using the formula: $F = C \times \frac95 + 32$

Requirements

• Take a f64 (floating point) parameter
• Return the Fahrenheit value as f64
• 100.0°C should return 212.0°F

Hints

• Be careful with integer vs float division
• 9.0 / 5.0 for float division
• Don't add a semicolon to your result expression!