diff options
Diffstat (limited to 'src/doc/book/listings/ch15-smart-pointers/listing-15-19')
4 files changed, 41 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-19/Cargo.lock b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/Cargo.lock new file mode 100644 index 000000000..a792c49aa --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/Cargo.lock @@ -0,0 +1,6 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +[[package]] +name = "cons-list" +version = "0.1.0" + diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-19/Cargo.toml b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/Cargo.toml new file mode 100644 index 000000000..dce1515c3 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/Cargo.toml @@ -0,0 +1,6 @@ +[package] +name = "cons-list" +version = "0.1.0" +edition = "2021" + +[dependencies] diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-19/output.txt b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/output.txt new file mode 100644 index 000000000..6a8cc8efe --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/output.txt @@ -0,0 +1,8 @@ +$ cargo run + Compiling cons-list v0.1.0 (file:///projects/cons-list) + Finished dev [unoptimized + debuginfo] target(s) in 0.45s + Running `target/debug/cons-list` +count after creating a = 1 +count after creating b = 2 +count after creating c = 3 +count after c goes out of scope = 2 diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-19/src/main.rs b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/src/main.rs new file mode 100644 index 000000000..1bd7bc533 --- /dev/null +++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-19/src/main.rs @@ -0,0 +1,21 @@ +enum List { + Cons(i32, Rc<List>), + Nil, +} + +use crate::List::{Cons, Nil}; +use std::rc::Rc; + +// ANCHOR: here +fn main() { + let a = Rc::new(Cons(5, Rc::new(Cons(10, Rc::new(Nil))))); + println!("count after creating a = {}", Rc::strong_count(&a)); + let b = Cons(3, Rc::clone(&a)); + println!("count after creating b = {}", Rc::strong_count(&a)); + { + let c = Cons(4, Rc::clone(&a)); + println!("count after creating c = {}", Rc::strong_count(&a)); + } + println!("count after c goes out of scope = {}", Rc::strong_count(&a)); +} +// ANCHOR_END: here |