4 files changed, 49 insertions, 10 deletions
diff --git a/works/life/computer-network-experiment/Output.cpp b/works/life/computer-network-experiment/Output.cpp
index 8efb525..e3dc69e 100644
--- a/works/life/computer-network-experiment/Output.cpp
+++ b/works/life/computer-network-experiment/Output.cpp
@@ -1,5 +1,9 @@
 #include "Output.h"
-#include "folly/CancellationToken.h"
+
+#include <folly/CancellationToken.h>
+
+#include <ostream>
+#include <type_traits>
 
 folly::MPMCQueue<Output> output_queue(100);
 
@@ -8,12 +12,29 @@ folly::CancellationSource cancellation_source;
 std::thread output_thread(OutputThread);
 
 void PrintOutput(const Output &output) {
+  std::basic_ostream<Char> *stream;
+
   switch (output.type) {
   case OutputType::Error:
-    error_stream << output.message;
+    stream = &error_stream;
     break;
   default:
-    output_stream << output.message;
+    stream = &output_stream;
+    break;
+  }
+
+  switch (output.color) {
+  case OutputColor::Normal:
+    (*stream) << output.message;
+    break;
+  case OutputColor::Green:
+    (*stream) << CRUT("\x1b[32m") << output.message << CRUT("\x1b[0m");
+    break;
+  case OutputColor::Red:
+    (*stream) << CRUT("\x1b[31m") << output.message << CRUT("\x1b[0m");
+    break;
+  case OutputColor::Yellow:
+    (*stream) << CRUT("\x1b[33m") << output.message << CRUT("\x1b[0m");
     break;
   }
 }
diff --git a/works/life/computer-network-experiment/Output.h b/works/life/computer-network-experiment/Output.h
index 22b913a..2d16eb0 100644
--- a/works/life/computer-network-experiment/Output.h
+++ b/works/life/computer-network-experiment/Output.h
@@ -3,19 +3,28 @@
 #include "StringUtil.hpp"
 
 #include <fmt/format.h>
+#include <folly/CancellationToken.h>
 #include <folly/MPMCPipeline.h>
 #include <folly/MPMCQueue.h>
-#include <folly/CancellationToken.h>
 
-#include <thread>
 #include <iostream>
+#include <thread>
 
 enum class OutputType { Normal, Error };
+enum class OutputColor { Normal, Green, Red, Yellow };
 
 struct Output {
   Output() = default;
   Output(String message, OutputType type = OutputType::Normal)
-      : message(std::move(message)), type(type) {}
+      : message(std::move(message)), type(type),
+        color(type == OutputType::Error ? OutputColor::Red
+                                        : OutputColor::Normal) {}
+
+  Output(String message, OutputColor color)
+      : message(std::move(message)), type(OutputType::Normal), color(color) {}
+
+  Output(String message, OutputType type, OutputColor color)
+      : message(std::move(message)), type(type), color(color) {}
 
   CRU_DEFAULT_COPY(Output)
   CRU_DEFAULT_MOVE(Output)
@@ -23,6 +32,7 @@ struct Output {
 
   String message;
   OutputType type;
+  OutputColor color;
 };
 
 extern folly::MPMCQueue<Output> output_queue;
@@ -43,6 +53,12 @@ void SendOutput(OutputType type, StringView format, Args &&...args) {
       Output{fmt::format(format, std::forward<Args>(args)...), type});
 }
 
+template <typename... Args>
+void SendOutput(OutputColor color, StringView format, Args &&...args) {
+  output_queue.blockingWrite(
+      Output{fmt::format(format, std::forward<Args>(args)...), color});
+}
+
 void OutputThread();
 
 void SignalAndWaitForOutputThreadStop();
diff --git a/works/life/computer-network-experiment/client.cpp b/works/life/computer-network-experiment/client.cpp
index 5d5075e..922ecdc 100644
--- a/works/life/computer-network-experiment/client.cpp
+++ b/works/life/computer-network-experiment/client.cpp
@@ -48,7 +48,8 @@ int Main() {
 
   std::string s(buffer, received_number);
 
-  SendOutput(CRUT("Received message:\n{}\n"), ConvertCharString(s));
+  SendOutput(OutputColor::Green, CRUT("Received message:\n"));
+  SendOutput(OutputColor::Normal, CRUT("{}\n"), ConvertCharString(s));
 
   CloseSocket(client_socket);
   return 0;
diff --git a/works/life/computer-network-experiment/server.cpp b/works/life/computer-network-experiment/server.cpp
index 14987f3..f12630a 100644
--- a/works/life/computer-network-experiment/server.cpp
+++ b/works/life/computer-network-experiment/server.cpp
@@ -49,7 +49,7 @@ void ResponseThreadProc(int socket, sockaddr_in address) {
     byte_count_sent += byte_actually_sent;
   }
 
-  SendOutput(CRUT("Succeeded to send message to {}!\n"),
+  SendOutput(OutputColor::Green, CRUT("Succeeded to send message to {}!\n"),
              ConvertCharString(address_string));
 
   CloseSocket(socket);
@@ -78,9 +78,10 @@ int Main() {
     PrintErrorMessageAndExit(CRUT("Failed to listen."));
   }
 
-  while (true) {
-    SendOutput(CRUT("Now start to accept incoming connection.\n"));
+  SendOutput(OutputColor::Green,
+             CRUT("Now start to accept incoming connection.\n"));
 
+  while (true) {
     sockaddr_in client_address;
     int client_socket;
     unsigned sin_size = sizeof(sockaddr_in);