Exercises Part 1, Section 1

ex_part_01_sect_01

// The `main` function is traditional program entry point.
pub fn main() {
    println!("Running exercises for section 1.1");

    let vec0 = Vec::new();

    // (*) (see exercises)
    let mut vec1 = fill_vec(vec0);

    // (**) (see exercises)
    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);

    vec1.push(88);

    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);

} // <-- Here, we hit the end of the scope for both `vec0` and `vec1`.
  //     The destructor for `Vec` will free any storage allocated to them.


// The `fill_vec` subroutine. Puts [22, 44, 66] into input vector,
// then returns it.
fn fill_vec(vec: Vec<i32>) -> Vec<i32> {

    // Move `vec` into new binding to make it mutable
    
    // (***) (see exercises)
    let mut vec = vec;

    vec.push(22);
    vec.push(44);
    vec.push(66);

    // transfer ownership of mutated `vec` back to caller
    return vec;
}