ch2: add ch2-needle-in-haystack.rs example

Author: timClicks

ch2/ch2-needle-in-haystack.rs

@@ -0,0 +1,15 @@
+fn main() {
+  let needle = 42;
+  let haystack = [1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862]; // <1>
+    
+  for reference in haystack.iter() { // <2>
+    let item = *reference; // <3>
+    if item == needle {
+      println!("{}", item);
+    }
+
+    // if reference == &needle { // <4>
+    //   println!("{}", reference);
+    // }
+  }
+}