added strings example

Author: BartMassey

README.md

@@ -8,3 +8,4 @@ in a controlled repository now.
 * `datatypes`: examples of various datatype thingies
 * `structs.rs`: struct and enum examples
 * `arrays.rs`: array and vector examples
+* `strings.rs`: string and str examples

strings.rs

@@ -0,0 +1,30 @@
+fn main() {
+    let mut s = String::new();
+    s.push('a');
+    s.push('b');
+    println!("{}", s);
+
+    let t = 5u32.to_string();
+    println!("{}", t);
+    let t = "ab".to_string();
+    assert_eq!(s, t);
+
+    let u = format!("{}{}", 'a', 'b');
+    assert_eq!(s, u);
+
+    /*
+    for i in 0..s.len() {
+        println!("{}", s[i]);
+    }
+    */
+
+    for c in s.chars() {
+        println!("{}", c);
+    }
+
+    let w: &str = "ab";
+    assert_eq!(s, w);
+
+    let w: &str = &s;
+    println!("{}", w);
+}