feat: simple set-like lookup

Sponsored-by: author

1 files changed, 77 insertions, 1 deletions

diff --git a/src/main.rs b/src/main.rs
index e7a11a9..ebb5c4f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,79 @@
 fn main() {
-    println!("Hello, world!");
+    let mut c = Container::default();
+    c.insert(42);
+    println!("{}", c.contains(42));
+    c.remove(42);
+    println!("{}", c.contains(42));
+}
+
+#[derive(Debug, Default)]
+struct Container {
+    numbers: Vec<i32>,
+}
+
+impl Container {
+    fn len(&self) -> usize {
+        self.numbers.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.numbers.is_empty()
+    }
+
+    fn contains(&self, n: i32) -> bool {
+        self.find(n).is_some()
+    }
+
+    fn insert(&mut self, n: i32) {
+        self.numbers.push(n);
+    }
+
+    fn remove(&mut self, n: i32) -> Option<i32> {
+        if let Some(i) = self.find(n) {
+            self.numbers.remove(i);
+            Some(n)
+        } else {
+            None
+        }
+    }
+
+    fn find(&self, n: i32) -> Option<usize> {
+        for (i, x) in self.numbers.iter().enumerate() {
+            if *x == n {
+                return Some(i);
+            }
+        }
+        None
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::Container;
+
+    #[test]
+    fn is_empty_initially() {
+        let c = Container::default();
+        assert_eq!(c.len(), 0);
+        assert!(c.is_empty());
+    }
+
+    #[test]
+    fn inserts() {
+        let mut c = Container::default();
+        assert!(!c.contains(0));
+        c.insert(0);
+        assert_eq!(c.len(), 1);
+        assert!(!c.is_empty());
+        assert!(c.contains(0));
+    }
+
+    #[test]
+    fn removes() {
+        let mut c = Container::default();
+        assert!(!c.contains(0));
+        c.insert(0);
+        c.remove(0);
+        assert!(c.is_empty());
+    }
 }