fn add(a: &str, b: &str) -> String {
    let mut string = String::with_capacity(a.len() + b.len());
    string.push_str(a);
    string.push_str(b);
    string
}
/// The add operation for strings.
The add operation for strings.
The add operation for strings .
fn add(a: &str, b: &str) -> String {
    let mut string = String::with_capacity(a.len() + b.len());
    string.push_str(a);
    string.push_str(b);
    string
}
fn add ( a : & str , b : & str ) -> String { let mut string = String :: with_capacity ( a . len ( ) + b . len ( ) ) ; string . push_str ( a ) ; string . push_str ( b ) ; string }
The add operation for strings.
The add operation for strings .
a
&str
b
&str
a
&str
b
&str