Rust

13.7    Solutions

This section provides the code solutions for the practice exercises in Section 13.6. The code is largely self-explanatory; however, we have included comments and additional explanations wherever necessary to enhance understanding.

1. Fixing the size calculation of unsized types

   use std::mem::size_of;fn main() {    println!("[i32] size is: {}", size_of::<&[i32]>());}  

2. Implementing correct handling of ?Sized trait bound in functions

   fn some_fn<T: ?Sized + std::fmt::Debug>(val: &T) {    println!("{:?}", val)}fn main() {}  

3. Implementing generic structs with dynamically sized fields

   struct FlexibleStruct<T: ?Sized> {    fixed_part: u32,    dynamic_part: T,}fn main() {    let instance = FlexibleStruct {        fixed_part: 42,        dynamic_part: "Hello"