GCD and LCM finding algorithim in RUST

cargo.tml

[package]
name = "bran1"
version = "0.1.0"
authors = ["Your Name <[email protected]>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
rustc-serialize = "0.3.24"
serde = "1.0.104"
serde_json = "1.0.45"
primes = "0.2.4"

main.rs

use primes::PrimeSet;

fn main() {
    let v = vec![1, 2, 3];

    println!("The {:?}", calc(v))
}

#[derive(Debug)]
struct Res {
    lcm: i64,
    gcd: i64,
}

impl PartialEq for Res {
    fn eq(&self, other: &Self) -> bool {
        self.lcm == other.lcm && self.gcd == other.gcd
    }
}

fn odd(num: i64) -> bool {
    let res = num % 2;

    if res == 0 {
        return true;
    } else {
        false
    }
}

fn is_there_odd_number(nums: Vec<i64>) -> bool {
    let mut odd_available = false;

    for i in nums {
        if odd(i) {
            odd_available = true
        }
    }

    odd_available
}

fn calc(nums: Vec<i64>) -> Res {
    
    // loop through nums calculating against prime numbers
    // checking if they are odd or even
    if(is_there_odd_number(nums)){
        
    }

    for i in nums {
        println!("Testing i64 {:?} is {:?}", i, odd_or_even(i))
    }

    let response = Res { lcm: 144, gcd: 6 };
    response
}

#[cfg(test)]
mod tests {
    // Note this useful idiom: importing names from outer (for mod tests) scope.
    use super::*;

    #[test]
    fn test_calc() {
        assert_eq!(calc(vec![12, 18, 48]), Res { lcm: 144, gcd: 6 });
    }
}