02_basic_calculator/06_while

Author: woojunro

exercises/02_basic_calculator/06_while/src/lib.rs

@@ -4,7 +4,15 @@ pub fn factorial(n: u32) -> u32 {
     // interprets as "I'll get back to this later", thus
     // suppressing type errors.
     // It panics at runtime.
-    todo!()
+    let mut i = n;
+    let mut ret: u32 = 1;
+
+    while i > 1 {
+      ret *= i;
+      i -= 1;
+    }
+
+    ret
 }
 
 #[cfg(test)]