medium.learning_rust.option..rs

// 01 - - - - - - - - - - - - - - - - - - - - - -
fn getIdByUsername(username: &str) -> Option<usize> {
    //if username can be found in the system, set userId
        return Some(userId);
    //else
        None
}

//💭 So on above function, instead of setting return type as usize
// set return type as Option<usize>
//Instead of return userId, return Some(userId)
// else None (💡remember? last return statement no need return keyword and ending ;)

// 02 - - - - - - - - - - - - - - - - - - - - - -
struct Task {
    title: String,
    assignee: Option<Person>,
}

//💭 Instead of assignee: Person, we use Option<Person>
//Because the task has not been assigned to a specific person

// - - - - - - - - - - - - - - - - - - - - - - -
//when using Option types as return types on functions
// we can use pattern matching to catch the relevant return type(Some/None) when calling them

fn main() {
    let username = "anonymous"
    match getIdByUsername(username) {
        None => println!("User not found"),
        Some(i) => println!("User Id: {}", i)
    }
}