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-rw-r--r--src/doc/book/listings/ch15-smart-pointers/listing-15-24/src/main.rs24
1 files changed, 24 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch15-smart-pointers/listing-15-24/src/main.rs b/src/doc/book/listings/ch15-smart-pointers/listing-15-24/src/main.rs
new file mode 100644
index 000000000..e225bd862
--- /dev/null
+++ b/src/doc/book/listings/ch15-smart-pointers/listing-15-24/src/main.rs
@@ -0,0 +1,24 @@
+#[derive(Debug)]
+enum List {
+ Cons(Rc<RefCell<i32>>, Rc<List>),
+ Nil,
+}
+
+use crate::List::{Cons, Nil};
+use std::cell::RefCell;
+use std::rc::Rc;
+
+fn main() {
+ let value = Rc::new(RefCell::new(5));
+
+ let a = Rc::new(Cons(Rc::clone(&value), Rc::new(Nil)));
+
+ let b = Cons(Rc::new(RefCell::new(3)), Rc::clone(&a));
+ let c = Cons(Rc::new(RefCell::new(4)), Rc::clone(&a));
+
+ *value.borrow_mut() += 10;
+
+ println!("a after = {:?}", a);
+ println!("b after = {:?}", b);
+ println!("c after = {:?}", c);
+}