struct Rec {
width : u32,
length : u32
}
fn process(rec1: Rec) -> Rec {
        let mut rec2 = rec1;
        rec2.width = 10;
    rec2.length = 11;
        rec2
}
fn main() {
                let rec = Rec{width : 4, length : 16};
                // rec.width = 100;
                // rec.length = 10;
                 println!("{},{}", rec.width, rec.length);
                 let mut rec2 =rec.clone();
                 rec2.width = 100;
                 rec2.length = 10;
                 println!("{},{}", rec2.width, rec2.length);
                 let rec3 = process(rec);
                 println!("{},{}", rec3.width, rec3.length);
}

 

[root@bogon clone]# cargo build
   Compiling own v0.1.0 (/data2/rust/clone)
error[E0599]: no method named `clone` found for struct `Rec` in the current scope
   --> src/main.rs:16:22
    |
1   | struct Rec {
    | ---------- method `clone` not found for this
...
16  |          let mut rec2 =rec.clone();
    |                            ^^^^^ method not found in `Rec`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `clone`, perhaps you need to implement it:
            candidate #1: `std::clone::Clone`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0599`.
error: could not compile `own`.

To learn more, run the command again with --verbose