字符串1: exercises/strings/strings1.rs ​

// strings1.rs
//
// Make me compile without changing the function signature!
//
// Execute `rustlings hint strings1` or use the `hint` watch subcommand for a
// hint.

// I AM NOT DONE

fn main() {
    let answer = current_favorite_color();
    println!("My current favorite color is {}", answer);
}

fn current_favorite_color() -> String {
    "blue"
}

fn current_favorite_color() -> String {
    "blue"  
    "blue".into()  
}

fn current_favorite_color() -> String {
    "blue"  
    "blue".to_string()  
}

fn current_favorite_color() -> String {
    "blue"  
    String::from("blue")  
}