src/main.rs

use std::io;

fn main() {
    println!("🩺 BMI Calculator");
    println!("Enter your weight in kilograms (kg):");

    let weight = match get_input_as_f64() {
        Some(value) => value,
        None => {
            println!("❌ Invalid input for weight. Please enter a valid number.");
            return;
        }
    };

    println!("Enter your height in meters (m):");
    let height = match get_input_as_f64() {
        Some(value) => value,
        None => {
            println!("❌ Invalid input for height. Please enter a valid number.");
            return;
        }
    };

    if height == 0.0 {
        println!("❌ Height cannot be zero.");
        return;
    }

    if weight == 0.0 {
        println!("❌ Weight cannot be zero.");
        return;
    }

    let bmi = calculate_bmi(weight, height);
    println!("✅ Your BMI is: {:.2}", bmi);

    let category = classify_bmi(bmi);
    println!("📊 BMI Category: {}", category);

}


fn get_input_as_f64() -> Option<f64> {
    let mut input = String::new();
    io::stdin()
     .read_line(&mut input)
     .expect("Failed to read input");


    match  input.trim().parse::<f64>() {
        Ok(value) => Some(value),
        Err(_) => None,
    }
}

fn calculate_bmi(weight: f64, height: f64) -> f64 {
    weight / (height * height)
}

fn classify_bmi(bmi: f64) -> &'static str {
    if bmi < 18.5 {
        "Underweight"
    } else if bmi >= 18.5 && bmi <= 24.9 {
        "Normal weight"
    } else if bmi >= 25.0 && bmi <= 29.9 {
        "Overweight"
    } else {
        "Obesity"
    }
}