References

Like C++, Rust has references:

fn main() {
    let mut x: i32 = 10;
    let ref_x: &mut i32 = &mut x;
    *ref_x = 20;
    println!("x: {x}");
}
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Some notes:

  • We must dereference ref_x when assigning to it, similar to C and C++ pointers.
  • Rust will auto-dereference in some cases, in particular when invoking methods (try ref_x.count_ones()).
  • References that are declared as mut can be bound to different values over their lifetime.

Speaker Notes

 Key points:
  • Be sure to note the difference between let mut ref_x: &i32 and let ref_x: &mut i32. The first one represents a mutable reference which can be bound to different values, while the second represents a reference to a mutable value.