[add] simply realization of fibonacci number

Author: FreeCX

src/27-fib-seq.rs

@@ -0,0 +1,14 @@
+fn fib_seq(n: u32) -> u64 {
+ let mut a: u64 = 0;
+ let mut b: u64 = 1;
+ for _ in 0..n {
+ let c = b;
+ b = a + b;
+ a = c;
+ }
+ a
+}
+
+fn main() {
+ println!("fib_seq(5) = {}", fib_seq(5));
+}