diff --git a/build.zig b/build.zig
index 8319bb4..6c5a073 100644
--- a/build.zig
+++ b/build.zig
@@ -1121,6 +1121,10 @@ const exercises = [_]Exercise{
         .main_file = "105_threading2.zig",
         .output = "PI ≈ 3.14159265",
     },
+    .{
+        .main_file = "106_files.zig",
+        .output = "succefully wrote 18 bytes.",
+    },
     .{
         .main_file = "999_the_end.zig",
         .output =