From 29dcb0c06fed27a5431a89d8bd89324c25f121e7 Mon Sep 17 00:00:00 2001
From: Alex Lai <74868436+Alx-Lai@users.noreply.github.com>
Date: Mon, 30 Sep 2024 23:15:50 +0800
Subject: [PATCH] Exercise: method and traits: change output (#2383)

In this exercise, the original StderrLogger output to stderr, which user
cannot see the original log but "No output" in frontend". Change
`eprintln!` to `println!` to make it see-able in the frontend. Also, due
to the change, rename the logger struct.

Close: #2382

Signed-off-by: Alx-Lai <alexabc722@gmail.com>
---
 src/methods-and-traits/exercise.md |  2 +-
 src/methods-and-traits/exercise.rs | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/methods-and-traits/exercise.md b/src/methods-and-traits/exercise.md
index d7d8830c627..21a80b46410 100644
--- a/src/methods-and-traits/exercise.md
+++ b/src/methods-and-traits/exercise.md
@@ -9,7 +9,7 @@ method. Code which might log its progress can then take an `&impl Logger`. In
 testing, this might put messages in the test logfile, while in a production
 build it would send messages to a log server.
 
-However, the `StderrLogger` given below logs all messages, regardless of
+However, the `StdoutLogger` given below logs all messages, regardless of
 verbosity. Your task is to write a `VerbosityFilter` type that will ignore
 messages above a maximum verbosity.
 
diff --git a/src/methods-and-traits/exercise.rs b/src/methods-and-traits/exercise.rs
index f7b9fa035cb..a51b4ad25b6 100644
--- a/src/methods-and-traits/exercise.rs
+++ b/src/methods-and-traits/exercise.rs
@@ -19,11 +19,11 @@ pub trait Logger {
     fn log(&self, verbosity: u8, message: &str);
 }
 
-struct StderrLogger;
+struct StdoutLogger;
 
-impl Logger for StderrLogger {
+impl Logger for StdoutLogger {
     fn log(&self, verbosity: u8, message: &str) {
-        eprintln!("verbosity={verbosity}: {message}");
+        println!("verbosity={verbosity}: {message}");
     }
 }
 // ANCHOR_END: setup
@@ -31,7 +31,7 @@ impl Logger for StderrLogger {
 /// Only log messages up to the given verbosity level.
 struct VerbosityFilter {
     max_verbosity: u8,
-    inner: StderrLogger,
+    inner: StdoutLogger,
 }
 
 impl Logger for VerbosityFilter {
@@ -44,7 +44,7 @@ impl Logger for VerbosityFilter {
 
 // ANCHOR: main
 fn main() {
-    let logger = VerbosityFilter { max_verbosity: 3, inner: StderrLogger };
+    let logger = VerbosityFilter { max_verbosity: 3, inner: StdoutLogger };
     logger.log(5, "FYI");
     logger.log(2, "Uhoh");
 }