diff options
Diffstat (limited to 'src/doc/book/listings/ch17-oop/listing-17-02')
3 files changed, 45 insertions, 0 deletions
diff --git a/src/doc/book/listings/ch17-oop/listing-17-02/Cargo.lock b/src/doc/book/listings/ch17-oop/listing-17-02/Cargo.lock new file mode 100644 index 000000000..471d8dfc3 --- /dev/null +++ b/src/doc/book/listings/ch17-oop/listing-17-02/Cargo.lock @@ -0,0 +1,6 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +[[package]] +name = "averaged-collection" +version = "0.1.0" + diff --git a/src/doc/book/listings/ch17-oop/listing-17-02/Cargo.toml b/src/doc/book/listings/ch17-oop/listing-17-02/Cargo.toml new file mode 100644 index 000000000..aed614e93 --- /dev/null +++ b/src/doc/book/listings/ch17-oop/listing-17-02/Cargo.toml @@ -0,0 +1,6 @@ +[package] +name = "averaged-collection" +version = "0.1.0" +edition = "2021" + +[dependencies] diff --git a/src/doc/book/listings/ch17-oop/listing-17-02/src/lib.rs b/src/doc/book/listings/ch17-oop/listing-17-02/src/lib.rs new file mode 100644 index 000000000..bb407ec5f --- /dev/null +++ b/src/doc/book/listings/ch17-oop/listing-17-02/src/lib.rs @@ -0,0 +1,33 @@ +pub struct AveragedCollection { + list: Vec<i32>, + average: f64, +} + +// ANCHOR: here +impl AveragedCollection { + pub fn add(&mut self, value: i32) { + self.list.push(value); + self.update_average(); + } + + pub fn remove(&mut self) -> Option<i32> { + let result = self.list.pop(); + match result { + Some(value) => { + self.update_average(); + Some(value) + } + None => None, + } + } + + pub fn average(&self) -> f64 { + self.average + } + + fn update_average(&mut self) { + let total: i32 = self.list.iter().sum(); + self.average = total as f64 / self.list.len() as f64; + } +} +// ANCHOR_END: here |