import ballerina/io;

function encrypt(string s, int key) returns string {
    final int offset = key % 26;
    if offset == 0 { return s; }
    int d;
    int[] chars = [];
    foreach int c in s.toCodePointInts() {
        if c >= 64 && c <= 90 {
            d = c + offset;
            if d > 90 { d -= 26; }
        } else if c >= 97 && c <= 122 {
            d = c + offset;
            if d > 122 { d -= 26; }
        } else {
            d = c;
        }
        chars.push(d);
    }
    return checkpanic string:fromCodePointInts(chars);
}

function decrypt(string s, int key) returns string {
    return encrypt(s, 26 - key);
}

public function main() {
    string encoded = encrypt("Bright vixens jump; dozy fowl quack.", 8);
    io:println(encoded);
    string decoded = decrypt(encoded, 8);
    io:println(decoded);
}