Shared via Rust Playground

playground.rs

#[derive(Debug)]

struct Pair(i32,i32);
fn eat(y:&mut Pair) { y.0 = 1; y.1 = 2}
//fn replace(y:&mut Pair) { y = Pair(1,2)} // no? why not?
fn replace(y:&mut Pair) { let Pair(x,z) = Pair(1,2); y.0 = x; y.1 = z}

fn main(){


let mut p = Pair(5,6);
let mut q = Pair(5,6);

eat(&mut p);
replace(&mut q);

//println!("{:?}", x);
println!("{:?}", p);
println!("{:?}", q);


}