strings

hash_maps/src/main.rs

@@ -0,0 +1,31 @@
+use std::collections::HashMap;
+
+fn main() {
+    use std::collections::HashMap;
+
+    let mut capitals = HashMap::new();
+
+    capitals.insert(String::from("Tokyo"), 43_000_000);
+    capitals.insert(String::from("Beijing"), 62_000_000);
+    capitals.insert(String::from("South Korea"), 29_000_000);
+
+    for (key, value) in &capitals {
+        println!("{key}: {value}")
+    }
+
+    let test1 = String::from("Tokyo");
+    let test2 = String::from("London");
+
+    let passing_test = get_population(capitals.clone(), test1);
+    let failing_test = get_population(capitals, test2);
+
+    println!(
+        "\npassing test: {:?}\nfailing test: {:?}",
+        passing_test, failing_test
+    );
+}
+
+fn get_population(capitals: HashMap<String, u32>, key: String) -> u32 {
+    let population = capitals.get(&key).copied().unwrap_or(0);
+    population
+}