completed lecture 31 - dynamic dispatch

Author: Colin MacRae

src/main.rs

@@ -0,0 +1,31 @@
+use std::mem;
+
+trait Printable {
+    fn format(&self) -> String;
+}
+
+impl Printable for i32 {
+    fn format(&self) -> String {
+        format!("i32: {}", *self)
+    }
+}
+
+impl Printable for String {
+    fn format(&self) -> String {
+        format!("string: {}", *self)
+    }
+}
+
+fn print_it(z: &Printable) {
+    println!("{}", z.format());
+}
+
+fn main() {
+    let a = 123;
+    let b = "hello".to_string();
+
+    // println!("{}", a.format());
+    // println!("{}", b.format());
+    print_it(a);
+    print_it(b);
+}