add: 8 projects

variables, shadowing, another_function, branches, loops, fahr2cel,
fibonacci, christmax_song

2 files changed, 42 insertions, 0 deletions

diff --git a/src/fibonacci/Cargo.toml b/src/fibonacci/Cargo.toml
new file mode 100644
index 0000000..15ac334
--- /dev/null
+++ b/src/fibonacci/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "fibonacci"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/src/fibonacci/src/main.rs b/src/fibonacci/src/main.rs
new file mode 100644
index 0000000..e5e973a
--- /dev/null
+++ b/src/fibonacci/src/main.rs
@@ -0,0 +1,36 @@
+use std::io;
+
+fn main() {
+    println!("Enter n:");
+
+    loop {
+        let mut user_input = String::new();
+
+        io::stdin()
+            .read_line(&mut user_input)
+            .expect("Failed to read line.");
+        
+        if user_input.trim() == "q" {
+            println!("Exiting.");
+            break;
+        }
+
+        let n: i32 = match user_input.trim().parse() {
+            Ok(num) => num,
+            Err(_) => continue,
+        };
+
+        let mut a: u64 = 0;
+        let mut b: u64 = 1;
+
+        // calc fibonacci[n]
+        for i in 0..n {
+            let next: u64 = a.checked_add(b)
+                .unwrap_or_else(|| panic!("overflow at {}", i));
+            a = b;
+            b = next;
+        }
+
+        println!("fibonacci[{n}]: {a}");
+    }
+}