src/main.rs

use std::io;

fn main() {
    println!("🔢Fibonacci Sequence Generator");
    println!("Enter the number of terms you want to generate:");

    let num_terms = match get_input_as_u32() {
        Some(value) => value,
        None => {
            println!("❌ Invalid input. Please enter a positive integer.");
            return;
        } 
    };

    if num_terms == 0 {
        println!("❌ Number of terms must be greater than zero.");
        return;
    }

    let sequence = generate_fibonacci(num_terms);
    let (evens, odds) = split_even_odd(&sequence);
    println!("\n✅ Fibonacci sequence ({} terms): {:?}", num_terms, sequence);
    println!("Even numbers: {:?}", evens);
    println!("Odd numbers:  {:?}", odds);

}

fn get_input_as_u32() -> Option<u32> {
    let mut input = String::new();
    io::stdin()
     .read_line(&mut input)
     .expect("❌ Failed to read input");

    match input.trim().parse::<u32>() {
        Ok(value) => Some(value),
        Err(_) => None,
    }
}

fn generate_fibonacci(n: u32) -> Vec<u64> {
    let mut sequence = Vec::new();

    if n >= 1 {
        sequence.push(0); 
    }

    if n >= 2 {
        sequence.push(1); 
    }

    for i in 2..n {
        let next = sequence[i as usize - 1] + sequence[i as usize - 2];
        sequence.push(next);
    }

    sequence
} 

fn split_even_odd(sequence: &[u64]) -> (Vec<u64>, Vec<u64>) {
    let mut evens = Vec::new();
    let mut odds = Vec::new();

    for &num in sequence {
        if num % 2 == 0 {
            evens.push(num);
        } else {
            odds.push(num);
        }
    }

    (evens, odds)
}