Add a bunch of code

Signed-off-by: Carlos Maiolino <[email protected]>

1 files changed, 62 insertions, 0 deletions

diff --git a/rust/refs_and_borrows/src/main.rs b/rust/refs_and_borrows/src/main.rs
new file mode 100644
index 0000000..212372b
--- /dev/null
+++ b/rust/refs_and_borrows/src/main.rs
@@ -0,0 +1,62 @@
+fn main() {
+    let m1 = String::from("Hello");
+    let m2 = String::from("world");
+
+    // Borrow m1 and m2 references to greet(), instead of passing ownership
+    greet(&m1, &m2);
+    let s = format!("{} {}", m1, m2);
+    println!("{s}");
+
+//    fing_it();
+//    aliasing_bonanza();
+//    mutable_bonanza();
+    flow_me();
+}
+
+// g1 is a reference that points to m1 on the stack, and m1 is a String
+// containing a box, pointing to "Hello" string on the heap.
+fn greet(g1: &String, g2: &String) -> () {
+    println!("Greet: {}, {}", *g1, *g2);
+}
+
+fn fing_it() -> () {
+    let mut x: Box<i32> = Box::new(1);
+    let _a:i32 = *x;
+    *x += 1;
+
+    let ref1: Box<i32> = Box::new(-5);
+
+    println!("This is sparta: {}", i32::abs(*ref1));
+}
+
+/*
+fn aliasing_bonanza() -> () {
+    let mut v: Vec<i32> = vec![10, 20, 30];
+    let num: &i32 = &v[2];
+    v.push(40);
+
+    println!("{:?}", *num)
+}
+*/
+fn mutable_bonanza() -> () {
+    let mut v: Vec<i32> = vec![10, 20, 30];
+
+    // let mut <var>  makes the VAR <var> mutable, i.e. it can be reassigned
+    // let <var>:&mut i32 = &mut foo creates an IMMUTABLE <var> that points to a
+    // mutable memory
+
+    let num: &mut i32 = &mut v[2];
+    let num2: &i32 = num;
+
+    println!("Index 2 == {}", *num2);
+}
+
+// Yes, moving { to the next line on purpose
+fn flow_me(strings: &Vec<String>, default: &String) -> &String
+{
+    if strings.len() > 0 {
+        &strings[0]
+    } else {
+        default
+    }
+}