From cb59f30a2e1cda87b8836793b1285fe37dda05ab Mon Sep 17 00:00:00 2001
From: Jannis Imhof <125810509+withjannis@users.noreply.github.com>
Date: Mon, 15 Apr 2024 22:07:44 +0200
Subject: [PATCH] Fix Fibonacci sequence i.e. fib(0) -> 0. (#1996)

related Issue #1985
---
 src/types-and-values/exercise.md | 7 +++----
 src/types-and-values/exercise.rs | 4 ++--
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/types-and-values/exercise.md b/src/types-and-values/exercise.md
index 1512208b..f12aec7c 100644
--- a/src/types-and-values/exercise.md
+++ b/src/types-and-values/exercise.md
@@ -4,16 +4,15 @@ minutes: 15
 
 # Exercise: Fibonacci
 
-The first and second Fibonacci numbers are both `1`. For n>2, the n'th Fibonacci
-number is calculated recursively as the sum of the n-1'th and n-2'th Fibonacci
-numbers.
+The Fibonacci sequence begins with `[0,1]`. For n>1, the n'th Fibonacci number
+is calculated recursively as the sum of the n-1'th and n-2'th Fibonacci numbers.
 
 Write a function `fib(n)` that calculates the n'th Fibonacci number. When will
 this function panic?
 
 ```rust,editable,should_panic
 {{#include exercise.rs:fib}}
-    if n <= 2 {
+    if n < 2 {
         // The base case.
         todo!("Implement this")
     } else {
diff --git a/src/types-and-values/exercise.rs b/src/types-and-values/exercise.rs
index f09513f4..01a8ad4a 100644
--- a/src/types-and-values/exercise.rs
+++ b/src/types-and-values/exercise.rs
@@ -16,8 +16,8 @@
 // ANCHOR: fib
 fn fib(n: u32) -> u32 {
     // ANCHOR_END: fib
-    if n <= 2 {
-        return 1;
+    if n < 2 {
+        return n;
     } else {
         return fib(n - 1) + fib(n - 2);
     }