caesar_cipher.rs

#![allow(non_snake_case)]

mod Caesar {
    pub fn encrypt(string: String, n: i32) -> String {
        let n = n % 26;
        let mut res = String::new();
        for char in string.as_bytes() {
            if !char.is_ascii_alphabetic() || char.is_ascii_whitespace() {
                res.push(char::from_u32(*char as u32).unwrap());
                continue;
            };
            if (char.is_ascii_lowercase() && *char as u32 + n as u32 >= b'z' as u32)
                || (char.is_ascii_uppercase() && *char as u32 + n as u32 >= b'Z' as u32)
            {
                res.push(
                    std::char::from_u32(
                        if char.is_ascii_lowercase() {
                            b'a'
                        } else {
                            b'A'
                        } as u32
                            + n as u32
                            - (if char.is_ascii_lowercase() {
                                b'z'
                            } else {
                                b'Z'
                            } - *char)  as u32 - 1,
                    )
                    .unwrap(),
                );
                continue;
            }
            res.push(std::char::from_u32(*char as u32 + n as u32).unwrap());
        }
        res
    }
    pub fn decrypt(string: String, n: i32) -> String {
        let n = n % 26;
        let mut res = String::new();
        for char in string.as_bytes() {
            if !char.is_ascii_alphabetic() || char.is_ascii_whitespace() {
                res.push(char::from_u32(*char as u32).unwrap());
                continue;
            };

            if (char.is_ascii_lowercase() && (*char as u32 - n as u32) < b'a' as u32)
                || (char.is_ascii_uppercase() && (*char as u32 - n as u32) < b'A' as u32)
            {
                res.push(
                    std::char::from_u32(
                        (if char.is_ascii_lowercase() {
                            b'z'
                        } else {
                            b'Z'
                        } as u32
                            - (n as u32
                                - (*char as u32
                                    - (if char.is_ascii_lowercase() {
                                        b'a'
                                    } else {
                                        b'A'
                                    }) as u32))) + 1,
                    )
                    .unwrap(),
                );
                continue;
            }

            res.push(std::char::from_u32(*char as u32 - n as u32).unwrap());
        }
        res
    }
}

fn main() {
    let encrypted = Caesar::encrypt(String::from("Hello, Worz! Encode and decode"), 7);
    let decrypted = Caesar::decrypt(encrypted.clone(), 7);
    println!("{encrypted} -> {decrypted}");
}