Code shared from the Rust Playground

playground.rs

fn bitcoin_block_reward(height: u64) -> u64 {
    let coin = 100000000.0;
    let reward_base = 50.0 * coin;
    let reward_halving = 210000.0;
    let result = reward_base / (2.0 as f64).powf((height as f64 / reward_halving).floor());
    result.floor() as u64
}

fn main() {
    println!("{}", bitcoin_block_reward(1489218));
}